Grounding beaten subject

[Bert Kemp]

I've read about all the posts on grounding, but theres so much conflicting advice that I'm still not sure if I should or shouldn't:eek: With re looping and stuff like that.
So yes or no answer.
How bout I just run the machines ground wire to the existing ground for my meter box. will that work and not cause additional problems??:confused:

[Dave Sheldrake]

How bout I just run the machines ground wire to the existing ground for my meter box

That's how UK systems are grounded Bert :)

cheers

Dave

[Bert Kemp]

I took that as go ahead and do it, so its done. Now i got to see if I can figure out lasercut and make the Rabbit run.


That's how UK systems are grounded Bert :)

cheers

Dave

[Tim Elmore]

Doing that is fine.

Really you just want a solidly connected ground in the event that the HV supply discharges to the body of the machine. Using the power socket in the wall doesn't guarantee a solid ground.

[Bill George]

I took that as go ahead and do it, so its done. Now i got to see if I can figure out lasercut and make the Rabbit run.

If its wired to Code the ground wire in the box should already be connected to that grounding bar in your Main box. My laser is just plugged into the grounded outlet. No issues.

BTW LaserCut is a piece of cake compared to the CAMfive laser I looked at purchasing used. I downloaded the Demo copy and it was so bad I decided just to keep what I had.

[Tim Elmore]

If its wired to Code the ground wire in the box should already be connected to that grounding bar in your Main box. My laser is just plugged into the grounded outlet. No issues.

The issue with this is that if the ground in the outlet fails and the power supply or supply arcs to chassis, you have potential for electrocution. Better to have a second ground, just in case.

[Bert Kemp]

Thanx everyone. I ran a ground wire from the lasers cabinet (the one thats already their)to the outside grounding rod thats attach to my homes grounding system

[Bill George]

The issue with this is that if the ground in the outlet fails and the power supply or supply arcs to chassis, you have potential for electrocution. Better to have a second ground, just in case.


Tim would that not be the case for everything plugged into any wall outlet?

I have and they sell them at most home improvement centers a little tester that plugs into each outlet and tells you if it has the white and black reversed or many other faults that outlet might have, including no actual ground.

In this case however its better to be safe than otherwise with the added tie in to the service ground. Still suggest checking all outlets.

[Tim Elmore]

Tim would that not be the case for everything plugged into any wall outlet?

I have and they sell them at most home improvement centers a little tester that plugs into each outlet and tells you if it has the white and black reversed or many other faults that outlet might have, including no actual ground.

In this case however its better to be safe than otherwise with the added tie in to the service ground. Still suggest checking all outlets.

20,000 volts has a whole lot more risk of electrocution than 120 volts. Completely different ballgames here, hence the need for a second layer of safety in place.

The tester is great, but connections can and do loosen over time. The extra ground wire cost $5. Its the same way that there's a laser interlock switch on the door, but we wear laser goggles as well (right?!).

Cheap insurance to protect life and retinas. I'm sure you'd feel bad if your advice resulted in injury or death to a fellow forum member.

[Dave Sheldrake]

20,000 volts has a whole lot more risk of electrocution than 120 volts.

Lots of volts Tim, practically no amps. Volts push, amps kill

cheers

Dave

[Bill George]

20,000 volts has a whole lot more risk of electrocution than 120 volts. Completely different ballgames here, hence the need for a second layer of safety in place.

The tester is great, but connections can and do loosen over time. The extra ground wire cost $5. Its the same way that there's a laser interlock switch on the door, but we wear laser goggles as well (right?!).

Cheap insurance to protect life and retinas. I'm sure you'd feel bad if your advice resulted in injury or death to a fellow forum member.

FYI the US National Electrical Code is more than likely the most restrictive wiring Code in the world. Far more than European or the Chinese. I would worry more about the Chinese lasers coming into the US with 120 volt rated outlets wired for 220 volts or the fact the older 2 prong European 220 volt wiring has no ground prong at all and some machines are still wired that way. Not everyone has access to a ground connection at the building service panel or grounding conductor. Testing the ground connection is the Only way to make sure its good and can carry the fault. If the machine is wired to Code and most Chinese machines are not and the person using the machine has a tested grounded outlet that is all that is required.

Far better than trying to find a true ground wire in a building other than the service entrance panel one.

FYI My own machine is just grounded by the tested outlet serving it, if someone wants to add a ground just make sure its from the same source as the main service panel.

[Tim Elmore]

Lots of volts Tim, practically no amps. Volts push, amps kill

cheers

Dave

I'm well aware of the biology involved. A laser PSU can supply 25-30ma easily.

The human heart can stop beating with as little as 20ma.

http://www.rense.com/general60/sspp.htm

[Dave Sheldrake]

Applied directly to it, true...

35mA is far less than the X25 disco pistol supplies (they are around 75mA and 55,000 volts)

Having been resting on a 200 watt machine (55mA and 42,000 volts) when it arcs to the chassis more than once I don't think the risk of death is too bad :)

That said if people feel safer by adding a ground spike that's all good. :)

cheers

Dave

[Tim Elmore]

35mA is far less than the X25 disco pistol supplies (they are around 75mA and 55,000 volts)

Tasers are NOT non-lethal.

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


Having been resting on a 200 watt machine (55mA and 42,000 volts) when it arcs to the chassis more than once I don't think the risk of death is too bad :)

....and I'm betting that machine was grounded.

Personally, safety is paramount. To each his own, but to gloss over the risks is irresponsible.

[Bill George]

....and I'm betting that machine was grounded.

If its plugged into a grounded outlet it was.

[David Somers]

Bill,

Your comment about Chinese electrical code not being as strict as ours was spot on. Or perhaps it is better to say they have a different approach than we do?

In my current order from China I had asked what amp circuits I needed on the laser and CNC devices. Both are 220 and they said they were wired for US standard. Anyway, they also included a photo of the plugs at my request. Both use a basic 110V style 15amp cord like you would find on any computer power supply. I thought that was interesting. If you wired your 220 outlet to that speck someone could easily come along and stick a 110V device into it since the plugs are the same. That would be amusing. They were curious when I mentioned this and wondered how we wired stuff. I sent them a chart of our plug and receptacle specs and explained they were designed to keep 110v stuff from plugging into 220 outlets. And to permit devices with a lower amperage draw to be plugged into higher amperage circuits, but not vice versa. Their response was pretty surprised. Interesting.

Anyway, I was originally going to wire my 220 outlets myself. But I think I might just wait till the units arrive and let an electrician do it so he can make sure things are correct for the devices and how they are wired. Better safe than miswired.

[Kev Williams]

Dave, I recently rewired mine, it's no sweat. Since my cords are exactly as you mentioned- the same exact cords we use here for 110v service- I just rewired the 110v socket that WAS powering my transformer before it blew. I've been going to change the socket to a 220 version, but so far I just made a red cover for it stating it's 220v for the laser.

The procedure I used to change over was this:

I already had a 20amp 220v breaker installed...

I Took the socket's black hot wire, and removed it from the 110v breaker it was connected to.

I connected it to one leg of the new 220v breaker.

I took the socket's white neutral wire, and removed it from the breaker box's neutral bus bar.

I connected it to the other leg of the new 220v breaker.

Ground was already connected.

That's it. I plugged in, everything worked...
==============

If you're starting fresh, just "pretend" there's no neutral wire, because there's not! The white is simply the second hot wire. It's a good idea to mark that wire with red paint or tape inside the breaker box, to indicate that it IS hot...

[Bill George]

What I found on mine is one wire is Red (hot?) the other is Green (neutral?) this is 120 volt from China. The third wire or ground wire is yellow/green from the plug on the machine and that wire goes through a wiring harness plug ( that can disconnect that ground), up into the wiring panel and is attached to a metal grounding area. The wire from the extra machine ground post is tied to the machine separately from the "other" Code required ground. So a person could if they want, pull apart that wiring harness plug to disconnect the required outlet grounding conductor and just use the extra machine ground post as a ground.
Someone needs to clue in the Chinese on US wiring Code and safety.

PS If your going to do as Kev suggests, make sure its a dedicated circuit, not one supplying your TV and sound system!!