# 350s in a 200 amp switch. Use a Tap box??



## Southeast Power (Jan 18, 2009)

I just decided to do the intercept and 3/0

Intercept existing oversized conductor leaving the electric room and terminate in tap gutter
Install new 480 volt 3 pole, 200 amp rated indoor non-SE rated ATS and connect between existing 200 amp 3 pole 600 volt fused main.


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## Cow (Jan 16, 2008)

We would run 3/0 through all the equipment and then either land the 350mcm on the load side lugs with pin adapters or leave them in a j-box adjacent to the switch and splice them onto 3/0 as it sounds like you're doing.


There is almost ZERO benefit to chasing 350's through all that 200A equipment for the little voltage drop reduction you may get. Probably .0001 volts difference over just using 3/0's. But, if you start using pin adapters everywhere, just to make them fit, that's just increasing the resistance from the additional splices/terminations. At that point you'd just be going backwards.


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## Helmut (May 7, 2014)

Does the ground wire from tap box to disconnects need to be sized for the 350's or the 3/0's?


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## Southeast Power (Jan 18, 2009)

Helmut said:


> Does the ground wire from tap box to disconnects need to be sized for the 350's or the 3/0's?


It’s EMT attached to bar joists so, I refuse to pull a ground wire.


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## Cow (Jan 16, 2008)

Helmut said:


> Does the ground wire from tap box to disconnects need to be sized for the 350's or the 3/0's?



If you're running 3/0's from a 200A fused disconnect, it only needs to be a #6. As soon as the 3/0's tap to the 350's, at that point, you would have to bump the EGC up proportionately.


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## Southeast Power (Jan 18, 2009)

We were quoting the job through a generator supplier. He decided to muddy the water by adding in a rental generator, a lease option and all kinds of complications.
Turnes out, they found some bottom feeder in Miami that would do the job "cheaper"
I'm happy for them.


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