Electrical – main electric circuit breaker – aluminium+copper contacts – put antioxidant grease

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I will be replacing main electric circuit breaker soon. Notice copper and aluminium contacts (this is the upper part of it, that goes to a meter) :

200 amps main electric circuit breaker

When I told this to my neighbor, he told me to check if I have to use antioxidant grease. Something like this (see the link). Can somebody please bring some light if this is required? My neighbor said he had to use it once for some AC electric work. That contact seems have both copper and aluminium contacts – why they would use different metals on the same contact?

Another photo on the same breaker (from a different angle) – Neutral on main service breaker? .

I do have a torque measuring tool as it has to be bolted with a particular force there. Is there is something else I should be aware of regarding this work?

Best Answer

I will answer it this way, I use anti oxide paste on even copper to copper lugs a bottle last many months and I do this for a living. Is it required ? I think it should be with any dissimilar metals but it helps prevent aluminum threads from oxidizing here close to the coast. I find jobs that the lugs are ruined from oxides and have to be replaced fairly often especially with large commercial equipment unless a little noalox or deox was used, look on the contact pointed of many new breakers and you will probably see just a drop, why do they put it there? It extends the life of the contact point and improves reliability. If mfg's do it why shouldn't we?

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