Copper Sheets

[danilo]

Gentlemen,
Im just curious about using copper sheets ( 20 sets of 1mmx 50mm)/phase as extension feeder from 1mva xformer terminals to low voltage cb with 1300A rated current.

what do you think are the advantages and disadvantages of using copper sheets over copper busbars?

regards,
Danilo

 

[cadpoint]

Isn't it: the sum of the whole is greater than the parts?
I don't think the OEM would let you use sheets but would sell you some bars. The AHJ would probably want a EE stamp on this.

Why sheets , anywas ?

 

[jim dungar]

Erico (I think) used to sell a laminated bus 'bar' assembly for just this purpose.

 

[danilo]

Isn't it: the sum of the whole is greater than the parts?
I don't think the OEM would let you use sheets but would sell you some bars. The AHJ would probably want a EE stamp on this.

Why sheets , anywas ?

its the original installed bus in the equipment and its for repair now..i think it was used to offset the bus onto cb terminals..the xformer terminals are not alligned with cb terminals..do you see an impact if this is to be retained?..its laminated and insulated by the way.

 

[Jraef]

Current is carried best on the surface of conductors, so layered* sheets are technically better than solid bars from that standpoint. Just like stranded wire vs solid wire. But they have worse emissivity, the ability to radiate heat, compared to a solid mass because heat from eddy current losses in the conductor surfaces has nowhere to go on the inner layers. So depending on the temperature considerations of your application, layered bus strips may have LESS ampacity than a similarly sized solid bar. In addition if subject to physical damage, a broken thin sheet stops conducting at all, putting more strain on the remaining ones, whereas a dented solid bar is no worse for the wear in that regard.

Layered strips are usually a lot more expensive as well. The only advantage they have is flexibility. It's usually very easy to bend then by hand to make things fit, as in your case.

*By the way, be careful with terminology. LAMINATED bus bar is an entirely different thing. That's where you have multiple layers insulted from each other to form separate pathways for current.

 

[danilo]

Current is carried best on the surface of conductors, so layered* sheets are technically better than solid bars from that standpoint. Just like stranded wire vs solid wire. But they have worse emissivity, the ability to radiate heat, compared to a solid mass because heat from eddy current losses in the conductor surfaces has nowhere to go on the inner layers. So depending on the temperature considerations of your application, layered bus strips may have LESS ampacity than a similarly sized solid bar. In addition if subject to physical damage, a broken thin sheet stops conducting at all, putting more strain on the remaining ones, whereas a dented solid bar is no worse for the wear in that regard.

Layered strips are usually a lot more expensive as well. The only advantage they have is flexibility. It's usually very easy to bend then by hand to make things fit, as in your case.

*By the way, be careful with terminology. LAMINATED bus bar is an entirely different thing. That's where you have multiple layers insulted from each other to form separate pathways for current.

Thanks Jraef, when you say LESS ampacity,could you give a derating factor as per NEC standard? and if some layered strips are loosed at its end,would its ampacity still be lessened?thanks

 

[Jraef]

Thanks Jraef, when you say LESS ampacity,could you give a derating factor as per NEC standard? and if some layered strips are loosed at its end,would its ampacity still be lessened?thanks

It's not that simple, but f you look at some bus bar manufacturer's web sites they often have emissivity charts based on the number of conductors layered and ambient temperatures.

 

[danilo]

It's not that simple, but f you look at some bus bar manufacturer's web sites they often have emissivity charts based on the number of conductors layered and ambient temperatures.

Thats a great input..thanks Jraef