Neutral wire gauge question

[sam]

Can someone please explain to me how I should properly step down my #6 AWG white neutral wire coming into my panel to the #14 AWG wires running to my pumps and other 120v devices?

I understand the hot wires are stepped down with breakers to protect the smaller gauge wires from current they can't handle but there aren't any breakers on the neutral wires. Can I just run the #6 into a din terminal block and branch out to the other devices with smaller wire?

 

[doug293cz]

Can someone please explain to me how I should properly step down my #6 AWG white neutral wire coming into my panel to the #14 AWG wires running to my pumps and other 120v devices?

I understand the hot wires are stepped down with breakers to protect the smaller gauge wires from current they can't handle but there aren't any breakers on the neutral wires. Can I just run the #6 into a din terminal block and branch out to the other devices with smaller wire?

You don't need to fuse the neutral step-downs, but you do need to make sure their are no loop paths that could allow higher than expected currents to flow in the smaller gauge neutral wires.

Brew on

 

[sam]

You don't need to fuse the neutral step-downs, but you do need to make sure their are no loop paths that could allow higher than expected currents to flow in the smaller gauge neutral wires.

Brew on

Thanks. Can you give me an example of what a "loop path" might be?

 

[z-bob]

The white neutral wire is protected by the breaker or fuse on its associated black (or red or blue) hot wire.

 

[doug293cz]

Thanks. Can you give me an example of what a "loop path" might be?

Don't have an example in mind. If I can think of one, I will try to describe it.

Brew on

 

[sam]

The white neutral wire is protected by the breaker or fuse on its associated black (or red or blue) hot wire.

Ah, yes, that makes sense to me. Thanks!

 

[jeffmeh]

No loop path could also be described as making sure none of the neutrals intended for your fuse/breaker protected 14awg circuit are connected to the 10awg circuit, yes?

 

[doug293cz]

No loop path could also be described as making sure none of the neutrals intended for your fuse/breaker protected 14awg circuit are connected to the 10awg circuit, yes?

Kind of. Maybe a better way to put it is: There should be no connections that would allow current flowing thru a 10 AWG hot wire to return (flow) thru a smaller gauge neutral wire. Remember, all current flowing in a hot wire must have a return path (the loop) either thru another hot wire that is out of phase, or thru neutral, or to ground (which would be a fault.) All current paths form a loop, and also loops may share legs.

Brew on

 

[sam]

Kind of. Maybe a better way to put it is: There should be no connections that would allow current flowing thru a 10 AWG hot wire to return (flow) thru a smaller gauge neutral wire. Remember, all current flowing in a hot wire must have a return path (the loop) either thru another hot wire that is out of phase, or thru neutral, or to ground (which would be a fault.) All current paths form a loop, and also loops may share legs.

Brew on

OK, cool. I understand it much better now. I was totally missing the return path concept (duh!) so didn't get the loop analogy.

In my case, I have all of my 120V devices connected to L1 (black wire), none on L2 (red). So, when measured, my neutral wire will always show the sum total of Amps drawn by all of my 120V devices.

Just as a quick thought exercise... if my panel displayed 26 Amps (23 Amps from the 240V 5500W element + 3 Amps from the two 120V pumps), I should see 3 Amps on the neutral wire which is the return path for the pumps. Now if, on the other hand, one pump was wired to L1 and the other to L2, the 120V loads would be balanced and I'd see 0 Amps on the neutral. Correct?

 

[z-bob]

You'd see approximately zero amps. Things never balance exactly, that's the whole purpose of the neutral wire (to carry the unbalanced load)

 

[doug293cz]

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