Surge protector or dedicated service?

[Bob Rath]

All...As I await the delivery of my new laser (Trotec 300...45w), I am now thinking about electrical issues. I'm curious how many of you on SMC have a surge protector between the 110v line service and your laser. If you do use a surge protector, any recommendations? Is a surge protector enough or is a dedicated APC type "clean" power supply necessary? Obviously there is a big difference in cost.

As always, Thanks

[Dave Russell Smith]

I put in a dedicated 20amp supply with surge protection

[Ted Owen]

I just KNEW you were going to take the plunge. Now don't go telling Chris this was all my fault. :)

Congratulations, Bob. When do you get to take delivery?

Best, Ted

[John Noell]

Our power fluctuates too much. So, (one logic board later) I use an APC line conditioner. Less expensive than a UPS and the typical UPS does not filter out highs until they are TOO high.

[Tania Duper]

Most electrical engineers that design these laser systems know about the electrical noise the units will be subjected to, in particular, with installations in commercial buildings that are ridiculously noisy.

Therefore, I'm sure most (all?) lasers will run fine without surge protection as there would already be elements in the circuits to protect against electrical problems. To be sure, you'd have to consult the manufacturer to see if they recommend surge protection.

Re: putting it on its own circuit, sometimes you can't put anything else on that circuit if it's already maxed out. For example, if the unit already draws 19 amps and you plug it into a 20 amp circuit, having even a PC plugged into the same line will throw the breaker every time.

Having a huge breaker is also a problem. For example, if you have a 40 amp breaker and the unit draws around 19 amps, you will fry the unit before it ever triggers the breaker.

The big Epilog 36EXT laser requires a 15 amp circuit minimum, and that should work even with their 120 watt laser. There really isn't enough current to worry about since 20 amp circuits are pretty common in the home. Just watch out you don't plug too many other things into that circuit. Worse case, is you trip the breaker. As long as you don't use a 40 amp breaker (or bigger) you'll be fine.

[Tania Duper]

Our power fluctuates too much. So, (one logic board later) I use an APC line conditioner. Less expensive than a UPS and the typical UPS does not filter out highs until they are TOO high.

I'm not sure if you can blame the logic board failure on unconditioned power. The job of the internal power supply is to condition the power and provide clean, and often different voltage & amps to the components.

It seems to me the board had a bad solder or component and it failed, or wasn't designed by a competent electrical engineer. Regardless, in this case conditioning (or lack of) isn't an issue. If there are any Epilog engineers reading this, I'm sure you'd agree and feel free to chime in.

[Randy Digby]

Bob, I've been responsible for a fair amount of electrical/electronics for a long time in an industrial setting. You don't run a $300,000.00 a month power bill without some electrically sensitive stuff being part of the mix. There is the one given - it's aways the smart and safe answer to have surge protection - and you still may take a hit someday.

We would use isolation transformers on DC drives (up to 800HP) and all sorts of grounding, phase monitors, conditioners, and the list goes on. Most of the time it worked - sometimes it didn't.

That being said, I would suggest you take stock of your electrical service history from what you already know. First, how is power delivered to your home/business (wherever the machine is)? Is it provided through overhead wires or is your service underground. I've lived in two houses served by underground electrical for the last 12 years and can't remember a "brown-out" or a visible power surge (where the ;ights actually get brighter). These things happen when wires get together with other wires, limbs, or the ground. Before we moved to an area with underground service, I can remember noticable variations almost everytime the wind changed directions. If your service is in the air, go for some type of protection.

You can still have all the protection you can think of and have the strangest things happen. Our office in in our residence and on carpeted floor. We try to always work bare footed or wear cotton socks. My wife forgot one day, came in from the outside and walked over to our M40 Gravograph to check a run she had going. She had forgotten to remove her shoes and when she touched the M40, I heard the arc across the room and the machine stopped in mid run. It didn't hurt it but it sure got our attention.

Good luck with your 300. We have had a 100 for six months now and it has been a great addition to our operation. Good luck and have fun...oh, and make some money too!!

[Rodne Gold]

I use 2.5 KVA power regenerators for our lasers , those big boxes that smooth and condition and convert to DC and back to AC ...lots of batteries in em - dunno what they called .. UPS Power invertors?
The reason was cos of banding effects when the power dips and surges - we are in Africa where power delivery is poor - apart from running all sorts of other machines in our building.
I can continue lasering for up to 1/2 an hour if we get a complete power failure with these units , but they werent particularily cheap however.

[Tania Duper]

Aside from huge fluctuations with environments of $300k/month power bills and using inverters or other devices that may not deliver a nice sine wave, yeah you may have problems. But in general, in America, these units aren't drawing enough power to worry about and I'm sure each of the laser manufacturers have taken poor power quality into consideration. Many of the cheap, consumer-based surge protectors & power strips with alleged surge protection aren't going to offer you any real protection and are just great marketing scams.

[Dan Hintz]

Most electrical engineers that design these laser systems know about the electrical noise the units will be subjected to, in particular, with installations in commercial buildings that are ridiculously noisy.

Therefore, I'm sure most (all?) lasers will run fine without surge protection as there would already be elements in the circuits to protect against electrical problems. To be sure, you'd have to consult the manufacturer to see if they recommend surge protection.

Re: putting it on its own circuit, sometimes you can't put anything else on that circuit if it's already maxed out. For example, if the unit already draws 19 amps and you plug it into a 20 amp circuit, having even a PC plugged into the same line will throw the breaker every time.

Having a huge breaker is also a problem. For example, if you have a 40 amp breaker and the unit draws around 19 amps, you will fry the unit before it ever triggers the breaker.

The big Epilog 36EXT laser requires a 15 amp circuit minimum, and that should work even with their 120 watt laser. There really isn't enough current to worry about since 20 amp circuits are pretty common in the home. Just watch out you don't plug too many other things into that circuit. Worse case, is you trip the breaker. As long as you don't use a 40 amp breaker (or bigger) you'll be fine.




I'm not sure if you can blame the logic board failure on unconditioned power. The job of the internal power supply is to condition the power and provide clean, and often different voltage & amps to the components.

It seems to me the board had a bad solder or component and it failed, or wasn't designed by a competent electrical engineer. Regardless, in this case conditioning (or lack of) isn't an issue. If there are any Epilog engineers reading this, I'm sure you'd agree and feel free to chime in.




Aside from huge fluctuations with environments of $300k/month power bills and using inverters or other devices that may not deliver a nice sine wave, yeah you may have problems. But in general, in America, these units aren't drawing enough power to worry about and I'm sure each of the laser manufacturers have taken poor power quality into consideration. Many of the cheap, consumer-based surge protectors & power strips with alleged surge protection aren't going to offer you any real protection and are just great marketing scams.
Tania,

You may want to spend some more time working with lasers in a range of locales before making such statements (I'm an MSEE, though I don't work for Epilog, and I disagree). Even the US-made units are susceptible to power issues, and even in the best of areas power isn't always as clean as it should be. Quite a few here have seen banding issues attributed to sagging/overrun power. While the power supplies are designed with quite a bit of capacitance in them for smoothing, major spikes and sags are out of the spec range for them and therefore they pass it along to the other components... a bad spike can quite easily take out the motherboard.

I'll agree that the engineering behind some of the circuits is lacking to some degree, but overall it's pretty decent. At least the companies appear to have left the difficult design work of power supplies to companies who make it their focus. That said, none of the systems are designed with industrial power grid issues in mind... if your company's grid is shifty, it's up to the facilities engineer to properly protect your equipment, not the equipment manufacturer.

Surge protection does not affect the operation of the machine (and therefore no company is going to suggest against it), but it can certainly help in the right circumstances... a non-direct lightning hit will almost certainly take out a non-protected machine along with quite a bit of other electronics in your house. A good quality inverter, such as what Rodney uses, will produce a clean sine wave and at the proper (and locked) frequency, regardless of external influences. Most of us don't need to go to the extreme of an inverter, but a good surge protector is a practical must, and a line conditioner is a must for more than just a few of us.

[Randy Digby]

Dan, this has nothing to do with the subject matter but something that you would understand and appreciate. We were a 17 mega-watt user fed with 150kv primary with automatic switch-over to a 46kv backup service after a power interruption of about .4 sec. When starting back up from an outage (planned or otherwise) we had to plan what equipment came online first because our plant inbound voltage (480v normally) would rise up to as much as 520v + with no load. We would have to bring on our heavy resistance load equipment first and just hope that the PLC's that ran those would handle the high input voltage. They usually did without problem, but we did use all A-B PLC's - they are expensive but they are reliable.

In the old days we would use large capacitor banks to keep the voltage managable. I never did like manually operating the buss plug switches to cut the capacitor banks in and out.

I'm glad that all I have to switch on now is that little red rocker switch.

[Mike Null]

Surge protection does not affect the operation of the machine (and therefore no company is going to suggest against it), but it can certainly help in the right circumstances... a non-direct lightning hit will almost certainly take out a non-protected machine along with quite a bit of other electronics in your house. A good quality inverter, such as what Rodney uses, will produce a clean sine wave and at the proper (and locked) frequency, regardless of external influences. Most of us don't need to go to the extreme of an inverter, but a good surge protector is a practical must, and a line conditioner is a must for more than just a few of us.


I agree 100%.
We had a lightning strike in the back yard that took out a controller panel and many electronics items including all cordless phones.

We get some severe thunderstorms here and I go so far as to shutdown equipment and unplug my engravers if it appears to be a major storm.

[James Rambo]

The summers in SW Florida are a bear for electrical discharge from the sky. If the storm is violent enough we also unplug our equipment. I have installed lightning and surge arrestors on the panel of the house. We also use a UPS for the computers that has a surge side large enough for the lazer to be plugged in also.

[Richard Rumancik]

Bob, you should have some type of surge suppression installed. What exactly and how much depends on what your power quality is like, your budget, and the risks you would like to take. It's like life insurance or fire insurance - chances are nothing will happen - but do you feel lucky?

The laser systems have very basic protection on the input. The power supply is not really intended to be a filter for bad power or surges. Although the laser system engineers are probably well aware of power quality issues they only put minimum protection into the machines and leave the onus on the customer to supply properly conditioned power.

I would not recommend that anyone install a laser without a minimum surge suppressor. If you don't have a big budget get a high-end computer-grade surge suppressor with at least a 3500 joules rating. Higher if you can find one. It should have 3 MOVs and say L-N, L-G, N-G protection. (line-neutral, line -ground, neutral-ground). (If you are running the laser on 240VAC then you might not be able to find a 240VAC computer-style suppressor, at least in N.A.)

You might consider getting a suppressor installed on the circuit at the power panel. A dedicated circuit is best (no compressors, arc welders etc on the same line.)

My own preference is an industrial quality UPS. Such as what is used for computer centers, telecommunications centers, ISPs, etc. They often have a rack-mount form factor. Often you can get a used one at a good price; install a set of new batteries for a couple hundred dollars and you are all set. My unit has buck/boost to control line voltage. I run it at 240VAC in and the laser on 240 as well. You can't plan on using it when the power goes out, but if you do have a loss of power it should have the capacity to enable a controlled shutdown of the system. You might find a new surplus one for less than $500. Keep in mind you will have to replace batteries every 5 years or so.

You might want to talk to an engineer at the local power utility. They often have someone on staff who will give you free advice as to what is appropriate for your situation. Sometimes they will even attach a monitor to your line and record disturbances for a period. My own local utility was only too happy to give me some suggestions.

[Dan Hintz]

Mike/James,

Having lived in Florida for 20 years, I unplug all major electrical equipment during major electrical storms, even though I now live in Maryland... it's simply not worth it to take the chance.

I have a UPS and surge protector on the computers, but so far have not spent the money to do the same for the laser other than a basic surge protector (though I finally bought the proper tools to measure current draw through the laser). Unplugging is the safest, but not the most expedient or convenient method to prevent damage.




Randy,

Back in high school (?) I visited a manufacturing facility (I think I was shilling for a part-time job for car money) that had a nice cap network in their backyard. The high-up I was talking with had a super-sized window in his office that was about as close to the network fenced area as I was comfortable getting. I was "lucky" enough to be there during a misty morning when they needed to raise the breaker bar. F-me, but the arc created as that bar swung away was freakishly large and powerful. Maybe that's why I never did better than a C+ when it came to power classes in school... high-power amazes and scares me at the same time, I never want to go near it.

[Tania Duper]

It's funny how a couple of you disagree with me, then change the terms by offering some pretty insane examples.

I said, in general, the power in America is just fine. Common sense would tell you to unplug equipment with crazy storms, etc. or to buy some impressive inverters or professional surge protectors when needed. When people are told to add surge protection, most of them will run out and buy the $3 power strips "with surge protection" and think they're just fine, which offers no additional protection that isn't already built into the power supplies.

Manufacturers either build their own power supplies or choose one based on the desired specs. If they planned for these things to run through the Van Allen radiation belt, laser systems would cost $50 billion each. So there is a point where manufacturers set the limitations and constraints because going beyond those levels are not only extremely rare, but get prohibitively expensive and why should everyone with stable power pay for a design to handle insane, potential conditions?

Therefore, save your money on the expensive, professional surge protection by just pulling the plug if you live in violent weather or serious industrial areas.

If you go back and read the initial message in this thread, the person asked if surge protection was "necessary". 99.9 percent of the time, no.

However, if you connect a lightning rod to your laser, you may want to think about some serious surge protection.

Let's be realistic and not have a contest on who can think up the most ridiculous situations.

[David Fairfield]

I also unplug during storms and when I leave for vacation. I unplug the female end, to which I added a little string loop, which I hang on a peg behind the laser where I can see it. That way I don't stand around scratching my head when the unit fails to boot up! :)

Dave

[James Rambo]

Tania as neither you or Bob show what your locations are I am telling you what I have as if you may live in our area. I believe that surge protection built into these very expensive machines is not enough for the area I live in. For a few months of each year we get violent storms almost every day. With lightning coming within the same block that I live in multiple time each storm. If I am not home or the lightning is in advance of the storm and if it strikes on the line it could be fatal to the electronics. I have seen it go through many components even after surge protectors. Wasting $100 for a little protection in my mind is worth it

[Tania Duper]

So then none of the manufacturers should bother with fuses.

The goal of the person who started this thread was to see if protection was required. The answer is, in general, 'no'. If Bob had said he lived in an area with radical power conditions he wouldn't even ask the question as everyone who lives in those areas has learned by now as they have lost many things over the years.

Each of the manufacturers have built products to withstand typical power conditions in most of America, otherwise they'd be replacing units within warranties every 5 minutes and they'd all go out of business.

Most people don't ask about their expensive TVs, home theater electronics, personal computers, or any other electrical appliances in their homes because pretty much everything built to plug into the national power grid has been designed accordingly.

Back in the day, way back, people would bring cattle prods into casinos and they'd hit the machine, causing the coin hopper motor to turn on until the machine was emptied. All slot machines that are built are actually tested with cattle prods by the various gaming boards before machines are approved for installation. Granted, lasers aren't typically subjected to cattle prods, but the point I'm trying to make is every somewhat competent EE knows about power, including those who design power supplies. Those who design the laser system want to make sure they're not replacing tubes and PCBs because they forgot to put some protection in their systems. I really wish some EEs from the laser manufacturers could comment as I'm sure they'd say, "are you kidding? Of course we put sufficient protection in there."

Now, in general, if you live in a crazy area, you already know to protect yourself even for your PC.

[Dan Hintz]

So then none of the manufacturers should bother with fuses.

The goal of the person who started this thread was to see if protection was required. The answer is, in general, 'no'.

Each of the manufacturers have built products to withstand typical power conditions in most of America, otherwise they'd be replacing units within warranties every 5 minutes and they'd all go out of business.

Granted, lasers aren't typically subjected to cattle prods, but the point I'm trying to make is every somewhat competent EE knows about power, including those who design power supplies. Those who design the laser system want to make sure they're not replacing tubes and PCBs because they forgot to put some protection in their systems. I really wish some EEs from the laser manufacturers could comment as I'm sure they'd say, "are you kidding? Of course we put sufficient protection in there."

I'm a "somewhat competent" EE, and you're becoming a troll on multiple threads where it's becoming obvious you don't know much more than what you've convinced yourself of.

I don't have to be working for a major laser manufacturer to tell you that your wrong. Quite a few products on the shelves out there were designed (at least in part) by me while working at various companies or as a consultant, and I can tell you without reservation that products are not designed with nasty electrical grids in mind... as you said earlier, the cost would be exorbitant. Excepting industrial equipment, products are designed to handle "normal" and "expected" variances in the power grid, with those two words being defined by the manufacturer on an individual basis. You do not have to live in an electrically active (i.e., storm) area to have problems with power... all it would take is for someone to knock over an electrical pole with their car, or a mainstream generator to up and lose its regulator before a massive surge hit the line (and yes, it happens). If you're close enough to it, your equipment is toast.

I can survive losing my $3k TV going down for a few weeks, I'll pull out a 25" CRT from storage and "suffer" for a while. But if I lose a $30k machine I use for making a profit, well, that's a bigger problem. I can protect that machine from such problems with <$100 in surge protection equipment, and that is a very good investment. This is protection that is NOT INCLUDED in the machines from the factory, and the reason for not including it has nothing to do with "the US power grid is ultra-stable", it has to do with the economics of the situation you pointed out earlier. If the manufacturers included it on their system, they are responsible for replacing it when it goes bad (say, after a lightning strike) under warranty. If the user installs it, it's up to the user to replace it. The manufacturers are generally nice and replace a fried board due to a lightning strike, even if the user didn't add extra protection, but they're not required to do so and will eventually deny warranty work if the user refuses to put in protection of their own when they're in an electrically active area.

To convince people their laser power supplies are already designed to handle problems like that is providing them with false hope. The fact that you insist on doing it after so many here have had issues due to power is wreckless as some newbie is bound to believe you.

And maybe it would be wise to let a "somewhat competent" EE tell you exactly what level of protection products are generally designed with rather than make a (false) assumption and spout it as truth... you know, as someone who isn't an EE and has obviously never had to design protection circuits.

[Michael Hunter]

All electrical and electronic equipment made in or imported into the EU must be CE marked for EMC emissions and immunity.
The immunity tests includes injecting fast transients ("spikes"), surges and "brownouts" into the AC supply whilst the equipment is in normal operation. The surges are 4kV for normal equipment (some equipment is tested to 12kV).
The manufacturer is allowed to declare the affect of these tests on his equipment, ranging from the best "keeps working as though nothing had happened" through to "needs operator intervention or resetting". The option "blows up and is rendered unusable" is (fortunately) not allowed.

The tests and procedures are described in the IEC/EN 61000 series, -4-5 being the surge tests.

Power supply manufacturers are well aware of the requirements and design their input and overvoltage circuits accordingly.

In the EU then, given connection to a "normal" electrical supply, it would seem that additional surge protection should NOT be necessary.
I should imagine that the quality of the power supply in well populated areas of the US would be at least as good as in thr EU.

In areas where electrical storms are heavy and frequent, some additional priotection may be warranted : note however that complete protection against lightning strike is almost impossible to achieve and the unplugging option would be well advised in these circumstances.

[Keith Outten]

Only plug in your laser engraver or other expensive equipment when you intend to use it.
Don't use your equipment in an electrical storm.
At the end of the day unplug!

Nothing protects equipment from a lightning strike. When I worked for Virginia Power we spent millions trying to come up with a means to protect some very expensive power plant breakers, nothing we tried worked and we had the most experienced people in the business working on the problem.

Epilog told me years ago when I purchased my laser engraver that the machine had surge protection built-in and there wasn't any need to use an external surge protector. I never have.

If you are going to purchase an inexpensive surge protector get one that includes insurance on any appliance that is plugged into it, the surge protector won't stop a major spike but the insurance might cover your loss.

The best ground you have is the one that comes off the electrical grid.......USE IT!
Don't rely on the ground rods that your plumbing and your electrical system are tied to, they are barely reliable when the gound has moisture in it.

A close or direct lightning strike will blow up your equipment and burn down your home or business......make sure you have insurance to cover your home and your business.

[Dan Hintz]

Michael/Keith,

Yes, an amount of surge protection is built in, but as with any good surge protection circuit it's a one-time shot deal... use and replace, if you will. I would rather replace a $100 external surge protector (APC offers great warranties on their products and up to $100k in insurance for anything connected to it) than a $500 power supply and have the machine down for a possibly extended period of time.



Michael,

EMC emissions/immunity ensures stray magnetic fields from the unit will not mess up, say, a patient's medical oxygen regulator during use. The UL declaration says, at a mnimum, that the device will not kill the operator under certain defined conditions, such as an open ground, etc. UL is about operator safety first and foremost, not about how the object will continue to operate after the fact... it's perfectly acceptable for the power supply to die completely, as long as the operator cannot be hurt afterward. UL certification is often regarded as the US equivalent of the European EU mark, but there are differences. Operator safety is a completely different animal than equipment surge protection.

Second, any surge protection for the power supply merely states that the power supply isn't damaged during the surge... it does not necessarily specify if equipment downwind of the supply sees any of that surge (and it usually does), hence why the PS can still be working and the sensitive motherboard is now dead.

[Richard Rumancik]

Keith, I don't doubt what you were told at the time by Epilog. As you can see there are a lot of opinions on the subject.


What Epilog DOES say is this:

Heavy Duty Surge Protector
The need for a surge protector varies greatly throughout the world. If the laser is operated anywhere that the electrical power is subject to spikes, outages, lighting, fluctuations, etc. a surge protector should be used on both the laser and the computer. A surge protector is a very, very cheap insurance policy against catastrophic electrical damage. A surge protector is designed to be an inexpensive device that absorbs any electrical problems before they can damage the expensive equipment (computer and laser) they are protecting.

This was from the Zing manual published 2009 but I found the same thing in a 2005 manual.

Everybody has their own idea of how much risk they want to take. There is no need for insurance of any kind if you have time and money on your side. To me, I agree with Epilog - a minimum surge suppressor is cheap insurance. Personally I would not run a laser (or computer or home theatre etc) without basic protection. The disruption to me as well as the expense is too painful.

Let's not berate anyone who elects to buy insurance. I would say more than 99.9% of the people who buy life insurance or fire insurance never collect a penny. That's a choice that gives them peace of mind. It's all a matter of how much risk you want to take. I don't think anyone here can PROVE you need a surge suppressor, no more than they can prove you need fire insurance. (And vise versa)


Edit: here is what ULS says on the VersaLASER

Providing a Suitable Electrical Power Source
· Never remove the ground (earth) lead to the electrical cord and plug the system into a non­grounded (non-earthed) outlet. Operating the device without the ground connection is very dangerous and can lead to a severe, if not fatal, electrical shock. It may also cause the device to exhibit unpredictable behavior.
· Noisy or unstable electricity as well as voltage spikes may cause interference and possible damage to the device’s electronics. If electrical power fluctuations, brown outs, or constant power outages are a problem in your area, an electrical power stabilizer, UPS (Uninterruptible Power Supply), or backup generator may be required.
· To prevent the overload of your electrical power circuit or to control an unstable or noisy electrical power source, it may be necessary to connect the device to a dedicated electrical circuit.

[Doug Lynch]

Thought I would chime in on this. I worked for a TV station and we had towers all over the state, the tallest tower was a 1000 foot tower out in the middle of nowhere. We always were having power problems, power bouncing around and had a lot of trash on it. We tried a lot of different things and some “helped” but nothing fixed the problems. As you might guess that 1000 foot tower was always getting hit with lighting. I bought the best devices I could find and the insurance that came with it. Well we got hit pretty bad one day during a storm and lost some equipment. I thought we were ok as I had the insurance. Long story short, after many phone calls I could not collect a dime as I could not “prove” lighting was the thing that blew out the equipment. They wanted me to provide them information that they knew I could not provide.

Doug Lynch

[Darren Null]

The profit in insurance is weaselling out of things they should pay.

[Dan Hintz]

Doug,

There really is no cure, even today, for a direct hit. Even from tens of feet away, a strike can be just as damaging... if it's a "direct" hit, you cross your fingers and hope nothing catches on fire (quite often the surge protection circuit does).

[Michael Hunter]

Dan

Possibly it is different in the US. The EN61000- series of standards is probably outside the remit of UL, since they are not primarily addressing safety.

In the EU, the standards quoted are to ensure that EQUIPMENT will survive the various AC mains supply faults which are unusual but not unforseeable.
There are separate standards for safety.

The standards are applied to the complete equipment, which is tested in all normal modes of operation. This means that if the PSU (from your example) does not properly suppress a surge and the motherboard dies, then that complete piece of equipment cannot be legally sold in the EU. Replacing fuses is OK, motherboards not!

Although the EU was in the forefront of this type of standard, the standards are international and other countries (including China) are now imposing them rigorously. This means that power supply manufacturers (and laser manufacturers who wish to export) apply the design principals necessary to meet the standards across all their products, without regard as to where they will be used in the world.


In a previous incarnation, I was "compliance officer" for an electronics manufacturing company and took many pieces of equipment through the tests (and sorted out the problems when they failed). The above is not guesswork.

[Richard Rumancik]

All electrical and electronic equipment made in or imported into the EU must be CE marked for EMC emissions and immunity.
The immunity tests includes injecting fast transients ("spikes"), surges and "brownouts" into the AC supply whilst the equipment is in normal operation. The surges are 4kV for normal equipment (some equipment is tested to 12kV). . . . The tests and procedures are described in the IEC/EN 61000 series, -4-5 being the surge tests.

Power supply manufacturers are well aware of the requirements and design their input and overvoltage circuits accordingly.

In the EU then, given connection to a "normal" electrical supply, it would seem that additional surge protection should NOT be necessary.
I should imagine that the quality of the power supply in well populated areas of the US would be at least as good as in thr EU. . . .

Michael, I realize equipment sold in the EU must be CE certified but some of the applicable standards and directives are chosen from a list depending on the nature of the equipment and its use. For example, it is more important that a piece of medical equipment be immune to voltage fluctuations as opposed to a piece of entertainment equipment eg wide screen TV. The mandatory requirements generally deal with emissions and safety.

The -4 and -5 tests you refer to do not seem to be mandatory for laser equipment. A manufacturer who passed these tests could use it as a marketing feature, but it does not seem that it is NECESSSARY for them to pass these tests. I am basing this on the CE Certification for the Zing - I just picked it as a current product which should be meeting the latest standards. It does not show compliance to the -4 and -5 standards you refer to, and appears to be marketed in Europe.

The ULS VersaLaser VLS 3.60 series seems to comply with selected sections on 61000-4 with numerous qualifiers. So they have picked tests which they feel are reasonable and achievable in their design and qualification.

You are implying that -4 and -5 standards are a requirement and then conclude that additional surge protection would not be necessary. However, laser systems might not be tested to those standards.

[Michael Hunter]

Richard

My main experience has been with "data processing equipment" and I agree that other types of equipment are subject to different sets of tests (though the manufacturer cannot pick and choose between particular tests, other than to declare the type/class of equipment that is to be tested).

My latest work in this field was an industrial microscope system (the electronics being laser diode illumination and a video camera) and that WAS surge tested. It was noticeable that in declaring that the equipment was for industrial use, much more emphesis was put on the mains purturbation tests than had been the case with the data processing equipment. Along with the CE certificate, I got one for FCC as the microsopes are exported to the US : unfortunately I don't know whether the immunity tests formed part of the FCC testing and I no longer have the certificates to hand. I did, however, have to put the normal wording along the lines of "must accept unwanted interference" which implies that the FCC at least takes an interest in these matters.

As far as I am aware, just about anything electronic and mains powered would be subject to the fast transient tests at a minimum of 4kV : failure of any component (other than a fuse) would lead to refusal of a test certificate.
Dan's suggestion that anything can blow so long as the operator is not hurt, whilst true for the narrow requirements of safety testing, does not apply for the bulk of equipment sold around the world.

The requirements change very frequently : when the CE mark was introduced the tests were rather theoretical, but since then the test houses and authority have gone a long way to ensuring that the tests reflect real-life situations. This means that older designs of machine may not have the same level of protection as new ones.

The easiest place to put in the necessary protection is in the PSU. As a design engineer, the introduction of the CE tests lead me to specify only PSUs which would give me the level of protection that I needed for the equipment (I did not want to fill my boxes with additional protection devices!). I was not alone in this and the PSU manufacturers were soon all pushing their latest "fully protected" PSUs.
My Epilog has a bought-in PSU and this, together with Epilog's statement that their machines do not need additional protection, leads me to think that I, and most other users, will be safe without it. This is very probably true of all the "big name" machines, wherever they are sold.

[Richard Rumancik]

Richard My main experience has been with "data processing equipment" and I agree that other types of equipment are subject to different sets of tests (though the manufacturer cannot pick and choose between particular tests, other than to declare the type/class of equipment that is to be tested).

Yes, for a given piece of equipment, some requirements are mandatory, particularly safety and emissions. The manufacturer CAN pick and choose from the non-mandatory tests and indicate what he does meet. This may be a marketing advantage, but not a requirement to get CE compliance.


My Epilog has a bought-in PSU and this, together with Epilog's statement that their machines do not need additional protection, leads me to think that I, and most other users, will be safe without it. This is very probably true of all the "big name" machines, wherever they are sold.

Not sure how the OEM power supply affects things. I interpret the Epilog statement differently . . . again, I have to say that it goes back to risk tolerance. I do agree that most users will be safe without it. But I would not suggest to anyone that they not use one.

[Dan Hintz]

Michael,

Make sure you aren't confusing EMI interference tests with surge or safety tests... your posts aren't quite clear that your making that distinction when you say a product passed test 'X'.

I'll reiterate what I said earlier about the UL mark... it may specify that nothing is damaged beyond a fuse, it does not specify that anything attached to the device is not damaged in the process. The UL/CE mark is strictly for the power supply and power supply alone, unless the entire system was tested as a unit (not likely due to expense and the requirement of having to check the entire system as a whole again anytime a schematic/BOM is changed). The PS may survive a 4kV spike (though quite possibly at a severely reduced lifetime), but nothing in those tests says the spike cannot be coupled back to the items being powered. This is a crucial distinction, as it says the only thing guaranteed to work after a major event is the PS... doesn't do much good if a 100V spike leaked through the PS and took out the mainboard's I/O control lines.

Anyone who is secure in their belief that the average at-home piece of equipment (TV, stereo, etc.) can handle a nasty transient quickly learns how fragile they actually are when a nasty storm comes to town and sends a few million volts @ several hundred amps into the ground near them or the local grid supply.

[Richard Rumancik]

I think we scared Bob away . . . Bob, are you still there? I guess you didn't expect to hear the strong feelings on this issue.

From your first post, I think that you were willing to get a basic surge suppressor and even willing to go further if you were convinced it was necessary. My advice (as before) is to at least get the basic suppressor, minimum of a high-end computer or home-theatre unit with 3 Movs and 3500+ joules absorption. Install a separate one for the computer. These should cost $50-$100 each.

If you have a bit more money talk to your power utility or an electrician. It wouldn't hurt to talk to Trotec and get their answer in writing. I couldn't find much about them on the Internet in terms of qualification testing.

There are a lot of new power quality devices (TVSSs, UPSs, whole-house filters for your power panel etc.) available on eBay at reasonable cost. Also, used UPSs are available. It does not have to cost a fortune. I bought a used UPS that was "new" in storage as a backup unit for a telecom. It was a couple years on the shelf but the batteries still lasted over 5 years.

It's great that the laser manufacturers are making products that are better than they were 10 years ago in terms of susceptibility, but the way I see it, once the warranty is up it is me paying the bill for repairs. And at that point it will not make much difference which EN standards they originally passed.

[Michael Hunter]

Dan

The CE mark is confusing because it covers a multitude of sins.

One of the reasons given for its introduction was to ensure that products are "fit for purpose" and that they will survive the commonly encountered mains perturbations, electrostatic sparks etc. - i.e directly aimed at stopping the "it didn't kill the operator so it must be OK" mentality so prevalent in the early days.

To obtain/declare a CE mark for mains-powered electronic equipment (e.g. "data processing equipment" [public display systems, payment tills and terminals] - which is what I know best) the complete product must be assessed for :
1 General safety - flamability, energy density and mechanical access to dangers etc. (a paperwork exercise similar to UL).
2 Electrical safety - separation of voltages, wiring capability/loading, insulation, grounding methods etc. (mainly paperwork but could include tests)
3 EMC emissions - RF, interference emitted back down the mains lead (similar to FCC) and interference emitted from any leads interconnecting separate parts of the system.
4 EMC immunity - RF fields, electrostatic discharge, mains-bourn interference, high voltage transients, high and low mains voltage, brownouts etc.

Although the product may assembled from subsystems that are themselves CE marked (PSU, display etc.), the WHOLE THING, set up as nearly as possible to real-life, must be tested for EMC.

The immunity tests are performed during "normal operation" and as I said before, the best result is that the system carries on regardless, whilst the worst is that the operator performs a reset.
The test houses don't like self-resetting systems since they can't tell what is going on - on occasions I was asked to provide special test software with the watchdog timer disabled.
A fuse blowing would be frowned upon, so you need to have a good excuse up your sleeve in case that happens.

In the case of the microscope that I did, a PC was needed to calculate and display the results of what the (CE marked) video camera detected, so the computer had to go into the test chamber too, being part of the "system".

In theory, the manufacturer can do their own paper assessment of the product and not perform any tests at all. In practice, customers in Germany and the Netherlands will often ask for a copy of the test house's report, so that really knocks self-certification on the head if you want to export. I have never known a product pass all the tests without some tweaking being needed somewhere.

The problem of parts going obsolete and having to be replaced is covered by a "technical construction file" which would include all the details of the original equipment as tested and copies of all subsequent engineering change notices which must include a section declaring whether the change is likely to impact any aspect of the original CE marking. I suspect that only the very most conscientious ever go back to the test house with an old product!