[Gmecm] Welding vs. computers

[Doug Chase]

It definitely makes sense to me that electronics could be subject to damage
if the proper precuations aren't taken.  Grounding to the chassis while
welding on the exhaust, for example, could have an O2 sensor as a casualty.

It also makes sense that completely removing components will protect them
from being damaged by things I haven't thought of.

What does NOT make sense is to why disconnecting the battery, a common
precaution I've heard, would protect anything.  It seems to me that it might
be even better leaving it in.  At least that way you have a very large
capacitor to protect against voltage spikes on the +12 side of things.
Thoughts?

Doug Chase
www.chaserace.com
425-269-5636

-----Original Message-----
From: gmecm-bounces at diy-efi.org [mailto:gmecm-bounces at diy-efi.org] On Behalf
Of bcroe at juno.com
Sent: Sunday, November 12, 2006 4:05 PM
To: gmecm at diy-efi.org
Subject: [Gmecm] Welding vs. computers

I second that.  Completely disconnect delicate electronics before welding.
A car isn't one mass of metal.  Many parts are isolated by rubber,etc.  So
things like ground straps and exhaust pipes may be taking big currents,
which aren't so predictable.  Not only the resistance is a factor, but the
arcing weld current will respond to inductance in the circuit.  If the
original ground system isn't in perfect condition, currents have been known
to find their way through things like shift cables.  

Do tie your welding ground to the piece of metal being welded, reasonably
close to the weld.  If there are 2 pieces, tie them electrically together.  

Bruce Roe

12 Nov 2006  Rexdina at aol.com writes:
> The fact is that while electricity does seek the path of least 
> resistance, not all of the current is going to necessarily do that. 
> Some of it can go through any of the numerous paths to ground. Best to 
> disconnect or entirely remove potential sensitive electronic 
> components. Yes, it's a hassle,  but so is trying to find out what is 
> "cooked" when you do ruin one. And it can  get expensive.
> Harry
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