Tap rules

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tim89s

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Brush Prairie WA
Here is the situation. I have 3 #1 CU conductors tapping off of 6 250 kcmil AL conductors. The 6 250's are fused at 350 amps. The #3's are going to a 90 amp disconnect. The distance between the tap and the disconnect is less than 25'. At this point I see no problem, due to the 25' tap rule. Let me know if you do. At the load side of the 90 amp disconnect three #4's and three #10's come off and go to a heat pump about 35' feet away. The #10's land on a contactor and the #4's go to a set of 45amp fuses. The #10's are for the compressor and fan. The #4's are for the heat strips. This is a definate violation of the tap rules, right? My question is how to fix the situation. One thought was set a disconnect at the unit and use the ten foot tap rule. So I would have a fused disconect within 25' of the 6 250's then come off the load side of that disconnect and go about 35' and set a disconnect on the heat pump itself. The disconnect would need to be fused, right? Is this considered tapping a tap? Any suggestions would be appreciated.

Thank you
Tim
 
In your first sentence you site 1 AWG tap conductors; in your second sentence you site 3 AWG tap conductors. I assume you mean 1 AWG because the 3 AWG conductors would be undersized.

I never heard of a 90 amp disconnect switch. You do not state whether this switch is fused. Seems to me if you put a 100 amp panel with a main breaker in place of the disconnect and provide branch circuit overcurrent protection for any loads leaving the panel, you should be in compliance

I'll be interested to hear what others say about tapping into parallel conductors. That is, do the 1 AWG tap conductors have to be connected to each of the parallel conductors or just one?
 
finhead said:
I'll be interested to hear what others say about tapping into parallel conductors. That is, do the 1 AWG tap conductors have to be connected to each of the parallel conductors or just one?


Both of the parallel conductors will have to be tapped. Paralleled means that the two are now one. I agree with the rest of your post.
 
The #10's of the 90A disconnect is the only problem I see. That could be fixed by adding another fusible disconnect near the 90A disconnect.

Then size the wire between the 90A disconnect and the new disconnect per one of the 10' or 25' tap rules.

Size the fuses and load side wiring on the new disconnect for the load. (I assume the #10 would probably still be OK.)

Steve
 
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