Tap Rules

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Sparky555

Senior Member
Help would be greatly appreciated from anyone with a working understanding of tap rules. The situation is as follows:

It's a single phase residence with a 400A service. There's a fused 400 amp disconnect by the meter pedestal. Inside the home each 400A wire is spliced with a pair of 200A wires. One set goes to a 200A fused disconnect for hot water baseboard heat, the other set goes to a 200A MB distribution panel. I'm assuming the 200A wire is allowed to be fused at 400A by a tap rule. The 200A wires are under 10 feet long.

My question is:
Am I allowed another tap on this 400A wire to another 200A distribution panel if the load calculation comes in under 320A?

Dave
 

infinity

Moderator
Staff member
Location
New Jersey
Occupation
Journeyman Electrician
Sparky555 said:
My question is:
Am I allowed another tap on this 400A wire to another 200A distribution panel if the load calculation comes in under 320A?

Dave

Yes this is permitted. Why are you limiting yourself to 320 amps?
 

charlie

Senior Member
Location
Indianapolis
stickboy1375 said:
80% silly, you can never use that last 20%.... :grin:
HUH? 215.2(A)(1) General. Feeder conductors shall have an ampacity not less than required to supply the load as calculated in Parts III, IV, and V of Article 220. The minimum feeder-circuit conductor size, before the application of any adjustment or correction factors, shall have an allowable ampacity not less than the noncontinuous load plus 125 percent of the continuous load. ;)
 

infinity

Moderator
Staff member
Location
New Jersey
Occupation
Journeyman Electrician
stickboy1375 said:
80% silly, you can never use that last 20%.... :grin:

The load calculation would already include 125% so your permitted calculated load is 400 amps.
 
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