8 Gauge Wire 200 amp disconnect

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mbrooke

mbrooke

Batteries Included
Location
United States
Occupation
Technician
Is 8 gauge wire on a 200 amp OCPD an allowable exception? What wiring method can be employed, ie does the wire have to be in a trough?

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Line side tap, or the fact this is a substation battery charger and doesn’t count.

I guess you would have a fit to find out S&C motor operators have slugs installed in them rather than fuses..
 
Hv&Lv said:
Line side tap, or the fact this is a substation battery charger and doesn’t count.

I guess you would have a fit to find out S&C motor operators have slugs installed in them rather than fuses..
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Aren't these conductors protected at their source, the battery charger, at 50A, the 200 fuse is not part of their protection. Is this why you say they "don't count"?
 
Hv&Lv said:
Line side tap, or the fact this is a substation battery charger and doesn’t count.

I guess you would have a fit to find out S&C motor operators have slugs installed in them rather than fuses..
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I can do that; I assume the batteries deliver the power, and exclude the charger.

Question- how do I find out the short circuit output of a battery bank?
 
mbrooke said:
I can do that; I assume the batteries deliver the power, and exclude the charger.

Question- how do I find out the short circuit output of a battery bank?
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Ask the battery people. Batteries can pump out a lot of current in a dead short situation but it is unlikely to be tens of thousands of amps.

P.S. - what makes you think you can run cord from the charger to the 200 A disconnect?
 
mbrooke said:
I can do that; I assume the batteries deliver the power, and exclude the charger.

Question- how do I find out the short circuit output of a battery bank?
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What’s the amp hour of the bank?
 
jim dungar said:
Aren't these conductors protected at their source, the battery charger, at 50A, the 200 fuse is not part of their protection. Is this why you say they "don't count"?
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90
.2(B)
jim dungar said:
Aren't these conductors protected at their source, the battery charger, at 50A, the 200 fuse is not part of their protection. Is this why you say they "don't count"?
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that and 99.2(b)
 
petersonra said:
Ask the battery people. Batteries can pump out a lot of current in a dead short situation but it is unlikely to be tens of thousands of amps.

P.S. - what makes you think you can run cord from the charger to the 200 A disconnect?
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That’s the charger circuit and it’s the way substation battery charger systems are generally wired.
Either that or direct to battery bank bypassing the disconnect, with a separate disconnect in the charger.
 
Hv&Lv said:
That’s the charger circuit and it’s the way substation battery charger systems are generally wired.
Either that or direct to battery bank bypassing the disconnect, with a separate disconnect in the charger.
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He seems worried about meeting code as far as the tap goes so why wouldn't he worry about the proscriptions on using cord.
 
Hv&Lv said:
90.2(B)

that and 99.2(b)
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Typo and not paying attention... 99.2(B) was a screwup

we generally run an 8 or 10 gauge duplex red/black for the charger circuit.
 
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jim dungar said:
90.2 is only applicable if this installation is a 'utility. I have designed and commissioned station battery systems like this for customer substations subject to the NEC.
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Correct. If the substation is customer owned, the NEC technically applies. But in any case it is still nice to know you have something that won't present excessive hazard to vital assets.
 
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