HF grounding

[hesstx]

Wanted to run this buy you guys to see if I did this right.

on the back of my Muti and tig units there is a Ground lug. I think I saw some where that you attach a ground cable to out with the HF light thing that happens to the lights when you weld.

I run a wire from outside that was placed to a 4 ft rebar beat all the way in. Ran the bare wire though to the work area but since I have 3 units and I move them around what is the best way to attach the ground. As in make a permanent attachment or a cable that wire clips or other attachment to a Central steel table that has a mill out it

Thanks
Hess

Do I even need the ground

[parkour]

HF grounding is a one possible solution to a problem.
You don't need it unless you're having problems.

[zoama]

The HF ground is totally unnecessary unless your having interference problems (television, computer, ect..). The HF ground only allows you to make a shorter path to ground and does nothing else.

[performance]

While not necessary, the damage done IF there is a problem, can be well worth it to do it every time. Considering you also have the HF hitting your internal components, and may have been a source of some failures, its a VERY good idea. When you have the biggest guys in the welder market telling you to do it, its worth thinking about, no doubt., even if you don't listen to us.

[parkour]

In light of what Mark has said, I think I should add that my initial statement was based on my aggregate impression of the experience of others based on what I've read on forums. Not that my lay opinion matters next to an expert, but I agree with Mark. I would, and should have, said that one should do whatever possible to affect the outcome to one's favor. Use the ground.

I am sorry for not saying that in the first place.

[hesstx]

While not necessary, the damage done IF there is a problem, can be well worth it to do it every time. Considering you also have the HF hitting your internal components, and may have been a source of some failures, its a VERY good idea. When you have the biggest guys in the welder market telling you to do it, its worth thinking about, no doubt., even if you don't listen to us.

So what is the best way to ground a unit that is mobile as in moveing around the shop and multiple unit. should I run a ground to a Central location then use a Temp ground like a small cramps like on a mini junper cble for each unit. Right now all units are on separate rolling carts and having a problem seeing 4 different ground wires running to a main on the wall. Hope you get the idea of what I'm saying

[zoama]

So what is the best way to ground a unit that is mobile as in moveing around the shop and multiple unit. should I run a ground to a Central location then use a Temp ground like a small cramps like on a mini junper cble for each unit. Right now all units are on separate rolling carts and having a problem seeing 4 different ground wires running to a main on the wall. Hope you get the idea of what I'm saying

The ground wires would have to be shorter than the your service ground to serve any purpose since the machine is already grounded to that. The object is to make a shorter path.

[performance]

So what is the best way to ground a unit that is mobile as in moveing around the shop and multiple unit. should I run a ground to a Central location then use a Temp ground like a small cramps like on a mini junper cble for each unit. Right now all units are on separate rolling carts and having a problem seeing 4 different ground wires running to a main on the wall. Hope you get the idea of what I'm saying

All you need is some 10-12 gauge stranded wire such as used for automotive at this point. A clip on the wire would make it easy to hook up. It should be run to a metal pipe or some other piece that goes directly in the ground.

As far as the ground needing to be shorter than the ground to the path...Don't worry...it will be. By the time it goes back to the panel and finds multiple paths to travel down it will be. Electricity doesn't just follow the shortest path. Think of having a splitter valve open on your water faucet. Then think of having both open with one having a 10 foot hose and another having a 20 foot hose. The water will eventually come out both hoses...more out of one to be sure, but it will still drain out of both. That's what happens with this sort of ground. You won't eliminate all HF, but you will greatly help. The shorter the wire, the better of course. But in our case of the example, if the 10 foot hose is the main ground that feeds back into the box then there are a dozen more hoses attached, as the ground ties into the box, it can back feed into other outlets. This is why it is important for computers to be electrically protected... and why when lightening strikes it gets some items and not others, although all may have received a jolt.

[Dublin]

Wanted to run this buy you guys to see if I did this right.

on the back of my Muti and tig units there is a Ground lug. I think I saw some where that you attach a ground cable to out with the HF light thing that happens to the lights when you weld.

I run a wire from outside that was placed to a 4 ft rebar beat all the way in. Ran the bare wire though to the work area but since I have 3 units and I move them around what is the best way to attach the ground. As in make a permanent attachment or a cable that wire clips or other attachment to a Central steel table that has a mill out it

Thanks
Hess

Do I even need the ground

First off, I'm not an electrician. But it appears from what you've written that you created a new ground rod. You need to tie whatever ground you run into the single ground rod servicing your shop. Having multiple ground rods creates a possibility for potential to develop between the rods creating damaging and potentially safety issues. Here's some reading on the subject:

http://ecmweb.com/grounding/avoiding...ustomers_0109/

[hesstx]

link must be down. I remember reading not to ground back to the panel so it must mean ground to the panel ground rod. Easy enough to do.

Thanks for the help

[Dublin]

Sorry, not sure why the link isn't working. Was working before! Anyway, here's a quote from a gentleman on another forum which sums it all up pretty well I believe:

Do not use an isolated ground rod. An isolated ground may appear to fix the issue but can be dangerous during electrical storms. Generally all grounded items like plumbing and structure are bonded together to prevent multipath and voltage differential issues. Isolated grounds are generally a violation of code.

Hope that helps.

[zoama]

Sorry, not sure why the link isn't working. Was working before! Anyway, here's a quote from a gentleman on another forum which sums it all up pretty well I believe:

Do not use an isolated ground rod. An isolated ground may appear to fix the issue but can be dangerous during electrical storms. Generally all grounded items like plumbing and structure are bonded together to prevent multipath and voltage differential issues. Isolated grounds are generally a violation of code.

Hope that helps.

It wouldn't be isolated because you're connecting back to your supply ground.... if I understand this correctly. (bonded vs isolated ground)

[parkour]

Here's a working link.
http://ecmweb.com/grounding/avoiding...ustomers_0109/

Don't disconnect the ground going to the panel from the machine. If the machine internally shorts one of the live mains input wires to the case, the ground wire will carry the current back to the panel and trip the breaker. A separate ground rod won't carry the current back to the panel so the breaker can trip. In that instance, the case could be electrified and nothing happen until you touch it.

[zoama]

Here's a working link.
http://ecmweb.com/grounding/avoiding...ustomers_0109/

Don't disconnect the ground going to the panel from the machine.

Why would anyone wanna do that ?

[parkour]

Not knowing any better along with a misunderstanding of grounding. Stranger things have been proposed.

If you're asking the question, and my statement apparently came out of nowhere; then I probably misunderstood something earlier in the thread. :(

[jerky]

all zoama said was the HF ground was to the chassis, as well as the ground from the power cable. my logic says then that the whole unit is grounded via the ground from power cable. so unless your ground in your power cable isnt grounded from your main panel, all should be good.

[hesstx]

In some reading there was a note not to use the panel ground but tie en below that but that really would not be doing anything

[Dublin]

I think the crux of what I was trying to say was to not install additional grounding rods in the ground. Run your second ground if you like but run it straight to the rod that is currently serving the rest of the household. You now will have two paths to ground assuming your power source/cable is grounded at the box. Multiple grounding rods allow for the possibility of potential to develop between them causing safety and other issues.
Cheers.

[hesstx]

I think the crux of what I was trying to say was to not install additional grounding rods in the ground. Run your second ground if you like but run it straight to the rod that is currently serving the rest of the household. You now will have two paths to ground assuming your power source/cable is grounded at the box. Multiple grounding rods allow for the possibility of potential to develop between them causing safety and other issues.
Cheers.

I bet that was what it was saying and makes since

Now that raises a another question?
I have 2 other small like 14 X 30 shops that feed off of the main shop panel to draw they power from. I placed a Grounding rd at each shop like the instructions for the panel box says , but would this work the same should I be working off the main ground rod

Thanks
Hess

[Dublin]

I really couldn't tell you. So much would go into determining whether or not potential could pass between the rods I'd be afraid to assume anything. The type of soil, moisture content, distance between rods, etc.... would all contribute to this decision. I would think the best thing to do would be to contact a licensed electrician and ask them to make a determination based on the NEC. If all the panels are fed from one location, I believe the NEC's stand is there should only be one grounding rod but what if your panels are 500 yards apart? I just don't know.....