Welding under overhead power lines

[F40]

I am going to be welding an aluminum box that is mounted on the back of my truck. The main power lines that feed my residential home are about 12 feet above the truck box, and the 200 amp service that feeds my garage enters at a point about 2 feet above the corner of the box. These service wires are insulated. I have never welded close to lines like this - Is this safe or are there any safety concerns I should know about? Any chance of arcing something like that? Thanks

[zapster]

Any chance of arcing something like that? Thanks


Only if you jab it with the mig gun or the stick...

Good ? though...
Dont you touch it however..:nono: :dizzy:

...zap!

[denrep]

... and the 200 amp service that feeds my garage enters at a point about 2 feet above the corner of the box...

Keep a keen eye out for Murphy!

[F40]

I should clarify that I will be welding inside the box and about 5 feet from the wire diagonally - which is outside the box. Anymore thoughts?

[PwrTurtle]

Can you move your truck so the box will be further away from the line?
Be careful getting in and out of the box.
Be REAL careful working in the box. Sounds like a lot of reflective surface in there.

[mwccwi]

5' should be plenty distance for safety, just be alert and pay attenion to you environment while you are working. You might look to see how the box is mounted and if it ground to anything. You didn't metion what the box is for, doing so might help the other members be able to offer informed advise.

[MAC702]

No danger unless you actually touch the lines. The hots are insulated, and you hope with good insulation, but they are likely wrapped around a bare cable, which serves two purposes. It is the messenger cable to take the weight, and also serves as the neutral conductor, which means it, too, carries current back to the grounded center-tap of the transformer. You CAN be electrocuted by this wire under fault conditions.

[F40]

I am going to do this early in the moring to avoid the heat. I will be working on top of a piece of plywood. The aluminum box is mounted on top of my F450. It is about 12 ft long and 6 ft high.

The wires to the garage are insulated. The overhead wires, 12 ft obove the box are not. I am not able to move the truck to another location unless I source the work out.

Am I safe to do this or not? I will take all the usual procautions. I have disconected the trucks batteries.....should I ground the truck by dropping a chain from the frame....or am I good to go as is. Like I said I will be working on the inside of the box and the wires that are about 2 ft from the top outside corner of the box are insulated - they come from exposed wires that are about 12 ft overhead. Thanks for all the advise.

[MAC702]

So, we're not worried about the uninsulated wires that are 12' overhead, right, just the ones to the garage? Does the garage feed have an insulated neutral?

Best NOT to ground the truck!! In fact, I'd make sure there were no metallic paths between the truck and the ground if I was in any kind of questionable situation.

[runchman]

this is completely off-topic but the ungrounded truck comment reminded me of it.

Ever seen the guys that work on the high-voltage lines, the real major ones... they hover a helicopter next to the line, and attach a cable from the copter to the line so they are both at the same potential, then they can work on the cable w/o getting zap-zowied.

Not work that I'd be willing to do !

- John

[MAC702]

Some of them wear a chain-mail suit, too, so current can flow right around them while they are in contact with the energized parts. Good pay!

[F40]

So, we're not worried about the uninsulated wires that are 12' overhead, right, just the ones to the garage? Does the garage feed have an insulated neutral?

Best NOT to ground the truck!! In fact, I'd make sure there were no metallic paths between the truck and the ground if I was in any kind of questionable situation.

Ya...I'm not worried about the overhead wires 12ft up. Just the garage feed. Both the hot and neutral are insulated wires. Only the ground is bare. The service is about 5 years old.

[MAC702]

I wouldn't give it another thought. I wouldn't intentionally poke them with a sharp stick, either.

Are you using equipment that comes from the garage's electrical at the time, or can you just shut off that circuit, if you really were worried about it anyway?

The garage feed is just a single 120V circuit?

[enlpck]

Additional note about the truck. It ISN'T ungrounded. The tires are not insulators. Not good conductors, but not insulators. The carbon black is the conducting component to the ground, and the steel belts insure that there is only a short path needed

[MAC702]

I agree. But for 120V?

[mwccwi]

F40'

supplied with the additional info, I'll dare say that your welding should a safe, just remember general safety precautions and to disconnect the negitive lead fron your truck battery so as not to fry any of your vehicles sensitive computerize components.
Good luck and have fun- some pictures after project completionwould be cool :)