Metal finishing Q&As since 1989

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Finish for aluminum bus bar application

2005

We make signs and are looking at using aluminum bus bars to keep the overall weight of the sign to a minimum. The bus bars are carrying 24 VDC and up to 60 amps. Connection to the bus bar will be made via a spring loaded, 5-position, single contact connector. All five of the positions are paralleled together to create redundancy. The connector carries 3 amps. Twenty boards in series creates the max 60 amps of current and this is handled by a 1/8"x1" Al bus bar.

The sign is used indoor in an or light industrial environment.

What do we need to concern ourselves with for this application?
Will fretting corrosion be an issue?
Can we leave this connection uncoated or do we need to select a coating of some type?
What coating would be recommended, if any?

Thanks,

Greg Schleusner
- Milw., WI

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Bare aluminum will oxidize slowly in air well past the point where a mere 24 volts will not consistently pass thru, then the joint will overheat, and fire will start.

This is the same reason aluminum is no longer used in home wiring with 120 volts.

The off/on contacting areas shold be at least tin plated. Gold would be better.

Robert H Probert
Robert H Probert Technical Services

Garner, North Carolina

2005