Plug a 70w Helix 24 into my 'welding outlet' (220 on 50amp breaker)

[Gary Hair]

Gary,

If you install 10 kA breaker on 14 gauge wiring all the wiring will burn before breaker will trip. You should never exceed breaker tripping for wiring and equipment specifications.

I exaggerated the value for a point, I would think that the wire capable of carrying 10 kA would be much more than you might find in your house...

[Mike Lassiter]

Wiring multiple 240VAC outlets on a single breaker is fairly common. In fact, I did it in my shop and the wiring inspector had no objections to it. The only drawback to doing it that way is if you happen to try to use two machines at once, then the breake r will trip. The same is true of 120VAC if you plug in two 1500W space heaters at once. The whole idea of breakers is to protect the structural wiring.

I beg to differ about it "being common". Didn't say it couldn't be done, but again NEVER have saw it done. That you did it in your shop and inspector passed it doesn't make it right. I would guess the inspector is really only concerned that the wire you ran the circuit with was heavy enough to carry the amp load of the breaker you had on the circuit. The fact that you are telling us that you trip the breaker when you try to use two machines at once sort of speaks for itself doesn't it? Was that your intention, when you wired it, to only be able to use one or the other at a time? As you noted about using two 1500 watt heaters at once tripping a breaker, that is why you can only have 3 outlets on a circuit in the kitchen (if I am remembering right - it's been awhile since I wired my previous house) because typically items used in the kitchen are high current draw items. Would serve no purpose to run every outlet in the kitchen on one breaker then have it trip every time you made coffee and used the microwave plugged in that sits on the counter. Sure you can wire them that way, but why would you if you wanted to be able to use more than one thing at a time.

[Gary Hair]

Gary, that is EXACTLY what a circuit breaker does - it limits the current the circuit can draw that it is protecting. My point was if the laser needs 15 amps and the power cord is sized for 15 amps having a 50 amp breaker to protect it is just stupid. The wires could melt and the breaker would NOT trip unless there was the 50 amps that it was rated for being draw. This would be NO protection basically for the circuit wiring. Normally in disconnect boxes you don't have a breaker at the source, it is a disconnect switch only. Could have fuses inside the disconnect box, but would still be protected by a breaker at the power distribution panel. After all you want the whole circuit protected against short circuit overloads not just between the disconnect and the device.

"A circuit breaker is a manually or automatically operated electrical switch designed to protect an electrical circuit from damage caused by overload or short circuit. Its basic function is to detect a fault condition and interrupt current flow"

http://en.wikipedia.org/wiki/Circuit_breaker

Nowhere does any definition say that it protects the equipment, it's exclusive purpose is to protect the circuit, period.

[Ronald Erickson]

I beg to differ about it "being common". Didn't say it couldn't be done, but again NEVER have saw it done. That you did it in your shop and inspector passed it doesn't make it right. I would guess the inspector is really only concerned that the wire you ran the circuit with was heavy enough to carry the amp load of the breaker you had on the circuit. The fact that you are telling us that you trip the breaker when you try to use two machines at once sort of speaks for itself doesn't it? Was that your intention, when you wired it, to only be able to use one or the other at a time? As you noted about using two 1500 watt heaters at once tripping a breaker, that is why you can only have 3 outlets on a circuit in the kitchen (if I am remembering right - it's been awhile since I wired my previous house) because typically items used in the kitchen are high current draw items. Would serve no purpose to run every outlet in the kitchen on one breaker then have it trip every time you made coffee and used the microwave plugged in that sits on the counter. Sure you can wire them that way, but why would you if you wanted to be able to use more than one thing at a time.

Running multiple 30 amp outlets on one circuit breaker in a garage/shop saves on wiring costs. You can typically only use one major tool in a shop at a time anyway if you are working in the shop alone, so why put in a dedicated circuit for each shop tool? It comes down to planning and how you use your shop. Having your table saw and planer on dedicated circuits may not make sense if you don't use both simultaneously; you'll save on wiring costs just extending the circuit to a second outlet and save on breaker space in the panel (which may have a limited number of spaces). That being said, having the dust collection on a seperate circuit from the table saw and lighting is a good idea because you'll use both the dust collection and the saw at the same time.

In the house (residential) is different. NEC does not limit the number of outlets on a circuit in residential work as they do with commercial work (however, in most cases you will want 12 outlets or less). The kitchen and bath do have specific requirements however (specifically for the reasons you stated: you need to run the coffee pot and the microwave at the same time) so you would be violating code to string all your kitchen outlets together on 1 circuit. In the kitchen, you need two 20 amp small appliance circuits that are only used for small appliances (no lighting).

Generally the following get their own dedicated circuit: range, wall oven, water heater, clothes washer, dryer, garbage disposal, dishwasher, furnace, well pump, permanently connected appliances (like heaters), permanently connected motors greater than 1/8 hp. In a shop setting, since your planer and table saw have plugs, they are not considered permanently connected and don't need dedicated circuits.

[Mike Lassiter]

"A circuit breaker is a manually or automatically operated electrical switch designed to protect an electrical circuit from damage caused by overload or short circuit. Its basic function is to detect a fault condition and interrupt current flow"

http://en.wikipedia.org/wiki/Circuit_breaker
Nowhere does any definition say that it protects the equipment, it's exclusive purpose is to protect the circuit, period.

quote me where I said the breaker is ONLY protecting the equipment! The equipment that is connected IS apart of the circuit that the circuit breaker is protecting. And to borrow your quote above:

it's exclusive purpose is to protect the circuit, period.

We agree the breaker is not intended to "protect" equipment from shorting out. Surely you have saw a freezer or other electric appliance that "failed" and was drawing excess current that wasn't a dead short. This happened to me a couple of weeks ago- not exactly in keeping with theme of message here, but applies to points made previously. I have been working on a double wide mobile home for about 1-1/2 years now for my daughter and family to move into. We had to removed decks and a covered front porch before the mover would move it. I have been making repairs as job and time allowed. We (I) ended up putting ceramic tile up beside stove and as a backsplash down kitchen counter for several reasons. Trailer had no empty breakers spaces in it. I installed an over the range microwave that requires a 15 amp circuit to it. Stove was gas, and original had pilot lights to light burners. New stove is pilotless ignition. Stove requires 10 amp circuit. Both power sources were on the same 20 amp breaker. I had to run a new wire from the breaker box to the outside wall of house and up to over the range microwave so the breaker wouldn't trip constantly. Funny that most of the lights are also on that circuit. Should have been better done, but it is what we got for a 20 year old mobile home. Anyway I had to pull receptacles and light switch out of the wall to put tile up on wall behind countertop. Understand I couldn't really kill circuit as all the lights were on it too, so I pulled everything out and CAREFULLY worked around them installing tile. The light switch for over the sink light and 1 receptacle are in the same box side by side. I bumped the light switch while grouting tile and pushed it into the receptacle beside it. Instantly all the lights went out, radio on counter out. Shorted hot screw on switch to ground screw on receptacle. Ok I expected the breaker to be tripped. This circuit was ran thru a GFI receptacle which tripped, and 20 amp breaker in breaker box also tripped. Still nothing working in house. Go back to breaker box and notice the 100 amp main also tripped. Reset it, and still nothing working. Went outside to service panel I installed and opened it to find the 100 amp breaker in there also tripped. Pretty amazed at how much stuff tripped off by brief contact. however, it was a "dead short" and I can see it doing that. 100 amp breaker wouldn't likely trip on overloaded circuit nor would a 50 amp welder breaker if something goes wrong in the laser and pulls more current than the cord can carry that connects it to the receptacle. I'm not talking about a dead short, I am talking about something wrong that is causing more current draw than normal, but still not a dead short. My argument is the laser is apart of the circuit while it is connected to power. The panel breaker isn't there to protect the laser as such, but it does limit the current the load can place on the circuit. That includes EVERYTHING from the wire attached to the circuit breaker to it's return back to the box.

[Art Mann]

I beg to differ about it "being common". Didn't say it couldn't be done, but again NEVER have saw it done. That you did it in your shop and inspector passed it doesn't make it right. I would guess the inspector is really only concerned that the wire you ran the circuit with was heavy enough to carry the amp load of the breaker you had on the circuit. The fact that you are telling us that you trip the breaker when you try to use two machines at once sort of speaks for itself doesn't it? Was that your intention, when you wired it, to only be able to use one or the other at a time? As you noted about using two 1500 watt heaters at once tripping a breaker, that is why you can only have 3 outlets on a circuit in the kitchen (if I am remembering right - it's been awhile since I wired my previous house) because typically items used in the kitchen are high current draw items. Would serve no purpose to run every outlet in the kitchen on one breaker then have it trip every time you made coffee and used the microwave plugged in that sits on the counter. Sure you can wire them that way, but why would you if you wanted to be able to use more than one thing at a time.

I don't mean to offend, but just because you haven't seen daisy chained 240VAC outlets doesn't mean it isn't common practice. I have seen it done routinely in many shop/garage situations. I have seen it in a commercial shop as well for little used equipment.

Please don't misquote me! I didn't say I trip breakers due to multiple machines running at once. I said that is the only drawback to using multiple drops on a single breaker. Most people find it very easy to reset a circuit breaker. That is a very minor drawback indeed considering the savings in wire and trouble installing so many different home runs. It is my standard operating procedure to run only one machine at once. There are exceptions - such as my dust collector - and I ran a dedicated circuit for it. There is certainly no safety risk involved if a breaker is tripped.

From my recollection, the NEC does in fact require separate circuits for kitchen appliances. I expect it is there to protect the consumer from annoying breaker trips. I have run all separate breakers in the kitchens I have wired because it just makes sense. Unlike the typical shop situation, someone might very well run a microwave and toaster oven at the same time.

[Mike Lassiter]

Art, I have saw welding receptacles tied together, because there was only 1 welder, and it couldn't be used in 2 places at once several times. Then later a plasma cutter comes along and someone is cutting while someone is welding... In an old building where wiring is hard to get at or run (like me running the wiring for the microwave down through the outside wall then between the belly board and floor about 30 feet then up inside an inside wall) it can be a pain!!! I wiring the building our equipment is in. I had the building built them I sorted out were everything would go. I popped chalk lines on the floor for things and where 120/240 receptacles needed to be, Ethernet and telephone too. Wiring is CHEAP when you are already doing it anyway, unless you are wiring a commercial building and running everything in EMT or ridge conduit. Common sense goes a LONG way in these things. Other than what I mentioned about 240 volts welder plugs I have never saw any shop I have worked in in almost 40 years that did it. I get it for a one man shop, and point taken there are exceptions to most anything. I have done my share of this stuff too.

[Art Mann]

One thing not mentioned is that your welder circuit is most likely a straight 240v circuit that uses 2 hots and a ground with NO NEUTRAL wire. If you don't have a neutral wire, you are not going to be able to convert the outlet into a subpanel without pulling another wire.

How many wires do you have at the outlet? Three (black, white (remarked as black or red), and ground) or four (black, red, white (not connected), and ground)?

Actually, I already mentioned the problem of the missing neutral wire. I certainly hope someone listens to one of us as it is likely to be a show stopper for all these suggestions.

[Art Mann]

Art, I have saw welding receptacles tied together, because there was only 1 welder, and it couldn't be used in 2 places at once several times. Then later a plasma cutter comes along and someone is cutting while someone is welding... In an old building where wiring is hard to get at or run (like me running the wiring for the microwave down through the outside wall then between the belly board and floor about 30 feet then up inside an inside wall) it can be a pain!!! I wiring the building our equipment is in. I had the building built them I sorted out were everything would go. I popped chalk lines on the floor for things and where 120/240 receptacles needed to be, Ethernet and telephone too. Wiring is CHEAP when you are already doing it anyway, unless you are wiring a commercial building and running everything in EMT or ridge conduit. Common sense goes a LONG way in these things. Other than what I mentioned about 240 volts welder plugs I have never saw any shop I have worked in in almost 40 years that did it. I get it for a one man shop, and point taken there are exceptions to most anything. I have done my share of this stuff too.

You have to take a look at the context in which all this discussion is being carried out. Someone said that the OP needs to swap out breakers to match the current draw of the laser machine he is going to plug into it. I pointed out that typical house wiring is full of examples where this isn't necessary or desirable. Most household appliances and just about all interior lighting fit into this category. That is where the multi-drop discussion got going. My shop is 24 X 28 and that is probably typical of many readers here. I have no desire to have someone else operating 240VAC equipment in my little shop at the same time I am. I was more than willing to take the chance that I might rarely forget and trip a breaker in order to save copper and labor when I wired my shop. The idea wasn't original with me as I have seen it done in a lot of hobby shops. As a matter of fact, I have seen that exact wiring strategy recommended several times on the SMC Woodshop forum.

In any case, breakers do not typically serve the purpose of protecting the equipment that are connected to them for the reasons I have already explained. That is accomplished by the equipment manufacturer and the common sense of the end user.

[Mike Lassiter]

my shop is 12x32 and my laser has a 240 volt dedicated circuit. Whole shop has surge protector installed in breaker box. I told him he needed to change the breaker. I would if I was planning to set up a large laser that will not be moved around and basically it will be dedicated to a specific spot and specific power source. In my setup, I can get to the breaker box and flip the breaker off MUCH faster than I could crawl around the laser and unplug it. The point about convenience outlets is taken and agreed with, however that is not the case here. Personally I would do what was suggest by 2nd or 3rd post. I would use that circuit and put in a branch power box and then run a circuit out of that to the laser. And as we are installing a 3rd laser, there is a good chance it will need a exhaust blower too. As I understood, he is already at the limit of the breaker everything else is running off of. Sure he can leave it like it is. I would not, you would it seems. Everybody has their own thoughts about it I guess. We have offered our opinions on it. He can decide what he wants to do, he may do something totally different from either of us....

[Rich Harman]

The purpose of a breaker is to protect the wiring, not the device that is drawing the power.

Sure, you can repurpose the breaker by replacing it with a smaller value in the hopes that it will offer protection to the appliance, but that is not what they are for - at least the wiring will remain protected.

It should be obvious - never replace a breaker for one that is a higher value, doing so means that the wiring is not protected.

[Duane Meadows]

. If you have concerns about over current then you need a line conditioner and/or a surge protector.

Umm, here we go again. Neither a line conditioner nor certainly a surge protector are to protect from over current. This point will be totally lost in the usual load of misinformation and argument that accompany all electrical questions.

Electronic components fail much to quickly for any size circuit breaker to prevent... even fast acting 3AG fuses don't open fast enough to protect a poorly design circuit. They usually open because the circuit failed. They may or may nor prevent secondary failures when they blow. An 80 watt laser power supply can totally self destruct and never trip a 15A breaker, let alone a 50A breaker. Assuming even only 50% efficiency, the needed supply pulls what, maybe 2 amps? Yes, I know that's just the laser, doesn't include support circuitry. Still...

If you decide to convert the 50A circuit to a branch panel, there is indeed the question of having a neutral!

Again I am sure this will be lost in the usual bickering on this forum!

[Art Mann]

There is absolutely nothing wrong with sizing a breaker to the minimum current you will need. However, just be aware that the additional protection you will get is approximately zero. See my previous explanation.

[Terry R Peterson]

I'm going to call Epilog later today to have this discussion with them to see what they have to say about using a Helix on 220. I'll post back their response "straight from the horses mouth".

I definitely got an slew on interesting and even controversial responses. To follow-up with the response from Epilog, they do have a 220v power cable available to the tune of $70 which I would be able to use in my situation. At that price, I'm going to further investigate the idea of turning my welding outlet into multiple 110's. I could use an extra outlet (one a separate breaker) to spread the load from the air compressors / exhaust fan / etc. anyway.

I know two here have asked what combination of wires I have (neutral and/or ground). I'll let the electrician answer that when he pulls my welding outlet to replace it with a breaker-box. The outlet is located 18" below my main breaker box, so no big deal if he has to pull new wire.

Thanks to each of you for your input. All was highly appreciated. Glad my first post to sawmill got some activity

[Glen Monaghan]

Mike, just for future reference, a simple strip of tape (electrician's, masking, whatever) over those screws is real cheap and easy insurance when you feel the need to work around live circuits. Quicker than stretching an extension cord and setting up work lights, too, just not as safe...