Underground runs of aluminum, size increased for VD, land in electrical room at an entrance point, then transition to copper in EMT which goes to various pieces of gear. Would the CU segment need to be upsized as well? For example 20ft of CU in EMT which hits a junction box, then 250ft of AL to the load. The 250ft of AL would be increased size for VD. Does the run of CU have to be upsized as well? Also wondering the best way to make that transition. Is there a terminal block with threaded studs where compression connectors can be used on the wire?
Transition from AL to CU, size and method?
- Thread starter Todd0x1
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winnie
Senior Member
- Location
- Springfield, MA, USA
- Occupation
- Electric motor research
Voltage drop is caused by the series resistance of the complete circuit. You can reduce voltage drop by increasing in size only a portion of the circult.
Lots of different ways to do such a transition; Polaris connectors are Cu/Al rated and easy to use.
-Jon
Lots of different ways to do such a transition; Polaris connectors are Cu/Al rated and easy to use.
-Jon
Beaches EE
Senior Member
- Location
- NE Florida
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- Electrical Engineer / Facilities Manager
Upsizing a major portion of the run does not require upsizing of the final few feet. At times a smaller conductor at the termination points is necessary due to (breaker) lug specifications.
You don't have to use the same size copper as aluminum if that is what you are asking. Your conductors need to be sized accordingly. If you run the whole circuit length in aluminum and the size needed to be 500mcm but if you did it in copper it needed to be 4/0, you could change sizes that way.
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