Different materials for busbars

[m sleem]

I'm in a project having different materials for equipment busbars,

All mv/lv cables are copper
RMU is tinned copper
TR is ALU
LV switchgear is silver plated copper
All switchboards are ALU
All power panels are copper

The RMU+TR+LV SG is unit substation type, what is your opinion for that mix?

 

[m sleem]

Any feedback?

 

[don_resqcapt19]

They are all acceptable materials. It is a design issue, not a safety or code issue.

 

[m sleem]

They are all acceptable materials. It is a design issue, not a safety or code issue.

Don, my concern is how to terminate these different materials between each others.

 

[jim dungar]

Don, my concern is how to terminate these different materials between each others.

Tin plate everything, as manufacturers have been doing for decades.

 

[Jraef]

Don, my concern is how to terminate these different materials between each others.

Just make sure all of your connectors are labeled as "Cu/Al", which, as mentioned, will mean they are tin plated, or an alloy that is designed for dissimilar contact.

My only concern might be the silver plating on the LV switchgear if this is in any kind of an environment that has the possibility of H₂S (hydrogen sufide) gas in the atmosphere. Silver reacts with H₂S to create "whiskers" of silver that grow on the connections and eventually lead to flash-over.
http://nepp.nasa.gov/Whisker/other_whisker/silver/index.htm

Any facility or process involving decomposing materials is a risk for H₂S gas formation; waste water treatment plants, pulp and paper mills, some chemical refining processes etc.

 

[m sleem]

Just make sure all of your connectors are labeled as "Cu/Al", which, as mentioned, will mean they are tin plated, or an alloy that is designed for dissimilar contact.

My only concern might be the silver plating on the LV switchgear if this is in any kind of an environment that has the possibility of H₂S (hydrogen sufide) gas in the atmosphere. Silver reacts with H₂S to create "whiskers" of silver that grow on the connections and eventually lead to flash-over.
http://nepp.nasa.gov/Whisker/other_whisker/silver/index.htm

Any facility or process involving decomposing materials is a risk for H₂S gas formation; waste water treatment plants, pulp and paper mills, some chemical refining processes etc.

Thanks for the very detailed information.