# Question.



## MikeFL (Apr 16, 2016)

Wire size is a function of the size of the OCPD protecting it.

A disco is not an OCPD. That disco can be rated a million amp and you don't need to change the wire size (except to fit the lugs).


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## wildleg (Apr 12, 2009)

I have worked places where the inspector made us install placards/labels with the max fuse size for buckets/panels with that situation, although I agree with the above.


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## Arikculwell (Feb 16, 2016)

So you are saying, its okay to wire to the fuse size not the disconnect size? I'm trying to avoid cutting/bending/using 1,000mcm. Since 400amp fuses only require 500mcm, that would be okay right?


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## Southeast Power (Jan 18, 2009)

Arikculwell said:


> I have a 600amp disconnect fused down to 400amp. Cany the supply wire's from CT box be 500mcm? Or must i wire to 600amp code with 1000mcm? Any refferenced to code book would be great aswell.


The switch is rated at 600amp Max.
Same thing if you used a 600amp breaker with a 400amp plug.


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## Dennis Alwon (May 9, 2009)

Arikculwell said:


> So you are saying, its okay to wire to the fuse size not the disconnect size? I'm trying to avoid cutting/bending/using 1,000mcm. Since 400amp fuses only require 500mcm, that would be okay right?


That is correct. Wire size should correspond to the overcurrent protective device. If someone wants more power later on they will have to change the wire and the overcurrent protective device.

Most people would not use 1000KCM but would use parallel runs of either 300 KCM or 350 Kcm


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