mig welding on metal building

[vallenbuch]

I need to do a little mig welding on the main support on a metal building. The building is a night club with computers neon lights and such and i wasnt sure if i needed to turn off breakers or unplug everything or if im worrying about nothing. Using a 90 amp 110 volt mig. Would appreciate any advice.

 

[KemppiFrog]

Hi and welcome.
Structural framing and 90 amp MIGs are not in the same sentance for me. What are you doing? Couple of brackets, or something structural. i.e. load bearing?
KF
Sorry, to your question, if the earth clamp is close to the weld area, doubt you have a problem. It is relatively low voltage compared to the night club kit.

 

[madkayaker]

90amp mig is capable of welding 2-2.5mm steel. So ok for a light bracket but no use after that.

As for risk of frying electrics as long as your "earth" clamp is a good electrical connection there is very little risk of any damage (welder earth and real earth is two different things)