What is the standard concerning wiring sizing after main disconnect prior to fusing. Example: 125 AMP incoming service ran to fuses for motor starter and also ran to ditribution block and stepped down to 12awg wire no fuses prior to block. I think this is incorrect but, have nothing but my gut feeling and instinct to go on. Can someone help?
wiring after disconnect
- Thread starter rswarrior
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petersonra
Senior Member
- Location
- Northern illinois
- Occupation
- engineer
Re: wiring after disconnect
this is pretty common wiring practice inside panels.
it is akin to the bus that is inside a panelboard.
somehow you have to branch out to the smaller loads. the short length of small wire is protected from overload by the downstream fuses. it is considered highly unlikely that the short length of wire will encounter a ground fault.
take a look at the tap rules in the code.
this is pretty common wiring practice inside panels.
it is akin to the bus that is inside a panelboard.
somehow you have to branch out to the smaller loads. the short length of small wire is protected from overload by the downstream fuses. it is considered highly unlikely that the short length of wire will encounter a ground fault.
take a look at the tap rules in the code.
james wuebker
Senior Member
- Location
- Iowa
Re: wiring after disconnect
rswarrior
I agree with you on this. If I'm reading correctly you have wires from the 125 amp service to a fusible disconnect for a motor. That wire is protected with the fuses. Now you also have # 12 wires coming off the feed to a D.
block and these wires aren't fused. That's not right and no way I could or would hook them up without the #12 wires being fused. If someone wanted to put several loads at that block and let's say it's a load that is 60 amps. That number 12 wire wouldn't hold very long. When ever you put a block like that in I always fuse that wire to the block. Again how this is wired you must fuse that #12 wire. Input from someone else!
Bye now,
Jim
rswarrior
I agree with you on this. If I'm reading correctly you have wires from the 125 amp service to a fusible disconnect for a motor. That wire is protected with the fuses. Now you also have # 12 wires coming off the feed to a D.
block and these wires aren't fused. That's not right and no way I could or would hook them up without the #12 wires being fused. If someone wanted to put several loads at that block and let's say it's a load that is 60 amps. That number 12 wire wouldn't hold very long. When ever you put a block like that in I always fuse that wire to the block. Again how this is wired you must fuse that #12 wire. Input from someone else!
Bye now,
Jim
charlie
Senior Member
- Location
- Indianapolis
Re: wiring after disconnect
The tap rules are set up like motor protection. The short circuit and ground fault protection is on the end where the feeder gets its power and the overload protection is on the load end. If you don't pay attention and add load to a tap, you may be able to overload the conductors. That is why only qualified persons are to work on the electrical system.
The tap rules are set up like motor protection. The short circuit and ground fault protection is on the end where the feeder gets its power and the overload protection is on the load end. If you don't pay attention and add load to a tap, you may be able to overload the conductors. That is why only qualified persons are to work on the electrical system.
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