Wiring neutral in a 200a fused disconnect.

[TheFlumph]

I got this https://www.homedepot.com/p/Siemens...-General-Duty-Fused-Outdoor-GF224NR/302352591 200a fused disconnect that goes between my feeder tap and my inverter. There are two poles for the hot wires and a ground bar. What do I do with neutral? does it just pass through the box?

Or is what I thought the ground bar is actually for neutral? Sorry if this is basic, Ive never worked with one of these.

and to my understanding, neutral never gets fused correct?

 

[zanydroid]

Hard to tell because the picture is a little low res.

Anything that is on plastic standoffs, is not the ground bar, or can be used as ground bar or as something else. If used as ground bar it likely has a green bonding screw that connects it to the enclosure.

If this is the service equipment the Neutral-Ground bond is formed there. Sounds like you are not using it that way.

Neutral can pass through for a disconnect of the kind you're talking about. But you will still need to bond ground to this enclosure.

Ground bars can screw straight into the enclosure (probably need to tap the holes in the correct location in the panel, probably towards the bottom).

 

[TheFlumph]

Hard to tell because the picture is a little low res.

Anything that is on plastic standoffs, is not the ground bar, or can be used as ground bar or as something else. If used as ground bar it likely has a green bonding screw that connects it to the enclosure.

If this is the service equipment the Neutral-Ground bond is formed there. Sounds like you are not using it that way.

Neutral can pass through for a disconnect of the kind you're talking about. But you will still need to bond ground to this enclosure.

Ground bars can screw straight into the enclosure (probably need to tap the holes in the correct location in the panel, probably towards the bottom).

Not for service, Its the disconnect in the below diagram.
also, heres the photo close up, it does have plastic standoffs.

so if my neutral wire is long enough, i can just pass it straight through right?

 

[zanydroid]

so if my neutral wire is long enough, i can just pass it straight through right?

Yes, up to you. This disconnect is probably set up to allow multiple feeders to split off it but you don’t have to use it that way.

 

[TheFlumph]

You're awesome, thank you.

 

[zanydroid]

and to my understanding, neutral never gets fused correct?

No fusing.

 

[TheFlumph]

Yes, up to you. This disconnect is probably set up to allow multiple feeders to split off it but you don’t have to use it that way.

ooh sorry one more thing. Ive got to mount this outside, and all my other stuff is inside in the basement. I see no need to even send the neutral out with it. Would it be a code violation if I sent the neutral straight from the feeder tap to the inverter instead of wasting money on the round trip to the disconnect?

 

[nuke]

ooh sorry one more thing. Ive got to mount this outside, and all my other stuff is inside in the basement. I see no need to even send the neutral out with it. Would it be a code violation if I sent the neutral straight from the feeder tap to the inverter instead of wasting money on the round trip to the disconnect?

I think it would be as it's a current carrying conductor and needs to be in the same conduit/raceway as the hots

 

[Supervstech]

I got this https://www.homedepot.com/p/Siemens...-General-Duty-Fused-Outdoor-GF224NR/302352591 200a fused disconnect that goes between my feeder tap and my inverter. There are two poles for the hot wires and a ground bar. What do I do with neutral? does it just pass through the box?

Or is what I thought the ground bar is actually for neutral? Sorry if this is basic, Ive never worked with one of these.

and to my understanding, neutral never gets fused correct?

View attachment 193139

So, this is after the main panel, before the inverter, correct?
If so, the neutral doesnt need to be broken, it can pass directly through the panel to the inverter.

IF this is between your utility meter, and the main panel for the house, it is a totally different case, and needs a neutral bus connection, and the PRIMARY AND ONLY ground bonding connection. And all downstream grounds seperated from neutral...

 

[TheFlumph]

So, this is after the main panel, before the inverter, correct?
If so, the neutral doesnt need to be broken, it can pass directly through the panel to the inverter.

IF this is between your utility meter, and the main panel for the house, it is a totally different case, and needs a neutral bus connection, and the PRIMARY AND ONLY ground bonding connection. And all downstream grounds seperated from neutral...

Ya, its between the main breaker at the meter, then the feeder taps, then this disco, then the inverter.
on the diagram I posted there is a feeder tap breaker, and transfer switch before the main load panel. That main load panel is where the ground is currently bonded to neutral. Im definitely only going to have one neutral ground bond.

I dont have it hooked up yet, Im planning mounting locations and estimating cable lengths.

 

[TheFlumph]

I found the code that makes me run the neutral with the other conductors. Its 300.3 B2

 

[zanydroid]

There are some cases where neutral needs to run out and others where it does not. If the current carrying conductors do not cancel each other out then you need to run neutral.

IIRC I worked it out before where imbalanced L1 L2 going out and back from a disconnect, 4 conductors in the same conduit, will cancel out. You will have to upsize the conductors for derating

If it goes a different path out from disconnect than in then most of the time you will need to run N.

This is the same argument for why a switched leg can go out and back on 12/2

 

[Supervstech]

ooh sorry one more thing. Ive got to mount this outside, and all my other stuff is inside in the basement. I see no need to even send the neutral out with it. Would it be a code violation if I sent the neutral straight from the feeder tap to the inverter instead of wasting money on the round trip to the disconnect?

Only time a neutral is allowed to not be run, is when it is feedi g a dedicated 240V load...
A disconnect prior to a main panel with ZERO 120V loads, and clearly marked, "for 240 loads only"
Otherwise, yeah, the neutral needs to be present.
It does not need to be connected in that panel though, but it must pass through it.

 

[zanydroid]

Only time a neutral is allowed to not be run, is when it is feedi g a dedicated 240V load...
A disconnect prior to a main panel with ZERO 120V loads, and clearly marked, "for 240 loads only"
Otherwise, yeah, the neutral needs to be present.
It does not need to be connected in that panel though, but it must pass through it.

How does code make the distinction between switched hot 120V leg and two switched 240V legs?

In the switched 120V case no neutral is run.

 

[zanydroid]

This has been discussed a few times, with something like 2:1 Nay vs Yay on whether a neutral needs to run to a disconnect.

It boils down to what the definition of "grounded conductor when used" means.

Neutral wire out to a disconnect and back?

If I run a circuit from a j-box inside to a disconnect outside and then back inside to the same j-box with all the conductors in the same piece of conduit (say 10' long) between the j-box and the disconnect, do you still need to run the Neutral out and back in even though the...

forums.mikeholt.com

Neutral required to be run to a disconnect?

Hello Hurk I wish we had Instructors like you when I went to Electric school.Most wouldn't have a clue and if they did they wouldn't try to explain it. I have been told like most in the trade that anytime you have a neutral feeding a multiple circuit to a disconnect you need to...

forums.mikeholt.com

 

[Supervstech]

If it has a 120v reference, n is required

 

[JBertok]

How does code make the distinction between switched hot 120V leg and two switched 240V legs?

In the switched 120V case no neutral is run.

I think it would be simpler if it were a single 240V hot and a Neutral. What we call "single-phase" is really "split-phase" or actually even 2-phase with the 120V sinewaves 180-degrees apart. Both conductors are hot, and both have 120V potential to ground and 240V between each other. The code for the neutral evolved over the last 30 years, for example since 1996, new-construction 30A dryer outlets have to be a 4-conductor NEMA 14-30R now instead of the old 3-conductor NEMA 10-30R which lacked a neutral. Similarly, I can recall back then it wasn't required to use handle tied breakers when feeding two split-phase shared-neutral circuits, but it has been required for a long time now.

 

[Hedges]

I think it would be as it's a current carrying conductor and needs to be in the same conduit/raceway as the hots

I found the code that makes me run the neutral with the other conductors. Its 300.3 B2View attachment 193163

There are some cases where neutral needs to run out and others where it does not. If the current carrying conductors do not cancel each other out then you need to run neutral.

IIRC I worked it out before where imbalanced L1 L2 going out and back from a disconnect, 4 conductors in the same conduit, will cancel out. You will have to upsize the conductors for derating

If it goes a different path out from disconnect than in then most of the time you will need to run N.

This is the same argument for why a switched leg can go out and back on 12/2

You don't want current of L1 going through one conduit, and return current of N going through a different conduit. If L1 & L2 enter switch box at top and exit at bottom, I would run N with them.

What I did at my old place was have the switch on a Tee off the conduit run. L1 and L2 went into the box, got switched, left through the hole they came in through. N ran past without entering the box. No upsize needed in this case because < 2' conduit off Tee, but I was using 2 awg and a 100A switch so only 80% anyway.

My new place (which I expect will be inspected more closely) I was going to do the same but didn't have the destination for N ready (and due to funny stuff going on at my main breaker, had to install it now.) So I used that standoff mounted lug for N. I mounted a ground bar on the box for G.