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Old 08-14-2017, 03:11 PM   #6
hfoster
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City: Cleveland
Vessel Name: Irishland
Vessel Model: Chris Craft Corinthian 380
Join Date: Mar 2012
Posts: 587
Quote:
Originally Posted by neurodoc View Post
Hi,
Yesterday I hired a guy to do some electric welding on my steel boat while I was somewhere else..
Shortly after arriving to the marina he called me to say he would not start welding if he had no access to the engine room to disconnect all the batteries.
I told him that all the switches were in "off" ... and he said that the only way of preventing "things" to happen was by physically disconnecting all terminals from the battery poles.
As I did not get what he meant, and did not want to argue about stuff I have never heard about, I told him to come back some other day.
Was the guy right? is there a reason to be concerned about?.
Mi primitive knowledge of electricity understands that the current involved in the process will only circulate between the electrode holder and the welding machine´s ground. Am I right?
What is your experience ?

Your welder was right and playing it safe. When welding a steel vessel you have to remember, in most cases it is sitting in water!


The whole vessel is one big ground and there could be a large arc anywhere throughout the vessel. That arc could damage things if they are grounded to the vessel.


Hence batteries are connected to the starter and the starter is connected to the motor and the motor in connected to the vessel.


The welder did not what to take a chance in frying something is all.

I hope that helps.

Cheers and best of luck.


H
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