Just a quick question on wiring. Can an aluminum feeder and a copper jumper be put under the same lug on a disconnect without having corosion problems? This is for some farm grain equipment. There will be two disconnects one 30A and one 60A. Both will not be used at the same time. Feeding the 60 with Al and need to jump to the 30 possibly with Cu and wondering if it will be alright to do.

Thanks for any quick replys

 

To answer your question, yes. But, you need to know this: Aluminum is commonly used on tinned copper buss bars in commercial applications. Anytime you contact two different metals under an electrical current, you are subject to corrosion. Aluminum, under a load, vibrates and subsiquently, causing resistance. Aluminum is commonly used on tinned copper buss bars in commercial applications.


There is a way to keep this oxidation to a mimimum. Use a NO-OX type product, which can be found at any hardware store or electrical supply house. The purpose of NO-OX lubricants is to prevent corrosion and lubricate the connection for easier maintenance. NO-OX electrical grease prevents corrosion attack, on all metal surfaces, from battery acid, salt, moisture and various industrial chemical vapors in the environment. When this conductive paste is used on aluminum connectors in joints, NO-OX prevents the reformation of oxide films, which cause high resistance and subsequent failures.

Hope this helps.

 

That's what I would use. Make sure you are not exceeding the load capability of the lug in the disconnect. They can get VERY hot.

 

Thanks. I have just finished up. Didn't use the paste but will definately keep that in the back of my head for next time. This was a remove and replace job and the previous "electrician" had put both together under the same terminal lug. I didn't see any reaction corrosion on the Al wire but did see some environmental exposure film. The disconnects had almost rusted away so I was there to replace them. All went well and thanks for the information on the NO-OX product. I will be on the lookout for some.

Thanks for responding