400A service with (2) 200A panels

[jaggedben]

Other than maybe a PVC box with thicker walls, I've never encountered an enclosure where a terminal adapter, or male adapter, as some call them, didn't come through enough to put a locknut and bushing on and have room after that. There is over a half inch of threads there after the locknut is on. Putting a sealing washer on the outside wouldn't lesson the thread exposure enough to prevent a locknut and bushing.

Yes a sealing *washer* on the outside works fine but a sealing *locknut* on the outside takes up a lot more thread space. As I said YMMV. I'm lucky if I get a full 1/2" of thread on my connectors. The point was that putting a sealing locknut on the inside meets code.

 

[Little Bill]

Yes a sealing *washer* on the outside works fine but a sealing *locknut* on the outside takes up a lot more thread space. As I said YMMV. I'm lucky if I get a full 1/2" of thread on my connectors. The point was that putting a sealing locknut on the inside meets code.

Be hard to put a sealing locknut on the outside when the male adapter goes in from the outside! The sealing locknut would have to go inside.
The OP is not dealing with a nipple.

 

[RdmanElect]

Be hard to put a sealing locknut on the outside when the male adapter goes in from the outside! The sealing locknut would have to go inside.
The OP is not dealing with a nipple.

Correct

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[Elect117]

Violations (NEC 2020) -

352.30 - Securely fastened within 3' of boxes, conduit bodies and any other terminations. Since the code says within 3', any stick less than 3' still needs to be secured.

240.21 - ATS service OCPD is 400A and you have 4/0 (AL or CU) from it in parallel to separate panels of a distance greater than 25'. To correct this, you can use that wireway above the panel boards as a place to splice. So install Polaris taps and then you can run the 4/0 to the panel since it is less than 25' (and maybe less than 10').

334.30 / 314.17 - NM cable (Romex) needs to be secured before it enters the box.

250.109 / 250.122 / 250.148 / 314.40(D) / 314.4 - After the Polaris taps, the largest OCPD for the gutter box is 4/0 so the EGC needs to be sized to the 400A OCPD and bonded to the box with all of the other EGCs (with circuits that are spliced) in that box.

 

[RdmanElect]

Are the lugs in the ATS rated for two wires?

Yes

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[ctsparks]

Lots of things not compliant in these pictures....

 

[kwired]

Are the lugs in the ATS rated for two wires?

If it is a 400 amp device, pretty likely they are.

 

[kwired]

From posts in the past - sealing locknuts apparently are listed for use with RMC/IMC and are supposed to be used on the outside of the enclosure.
They are not listed for use with PVC TA's or other "connectors" for that matter, though they are rather effective.

Someone posted an image of a catalog page that had the mentioned Carlon washers somewhat recently. FWIW, I remember seeing and commenting that the foot note on that page mentioned they are not listed. So essentially they are no better or worse from perspective of what is listed than the sealing locknut is. Myers hubs aren't listed for use with anything besides threaded RMC/IMC either, but would still likely be my choice of what to use in such a situation.

 

[kwired]

Something I haven't seen mentioned yet is the length of conductors of each parallel set of conductors - the ones between the meter socket and the main breaker. The "inside" run is shorter therefore has less resistance. Doesn't seem it would be very significant but the reason you are supposed to keep them the same length is so they have as close as possible to same resistance and that will help make current divide equally. If there is enough difference this can result in one conductor being overloaded and the other one being lightly loaded when the draw is high. On a dwelling and depending on demand situations this maybe wouldn't happen very often.

 

[hillbilly1]

If it is a 400 amp device, pretty likely they are.

But not always.

 

[Little Bill]

But not always.

Usually they are dual lugs instead of single lug rated for two conductors.

 

[RdmanElect]

Something I haven't seen mentioned yet is the length of conductors of each parallel set of conductors - the ones between the meter socket and the main breaker. The "inside" run is shorter therefore has less resistance. Doesn't seem it would be very significant but the reason you are supposed to keep them the same length is so they have as close as possible to same resistance and that will help make current divide equally. If there is enough difference this can result in one conductor being overloaded and the other one being lightly loaded when the draw is high. On a dwelling and depending on demand situations this maybe wouldn't happen very often.

Thank you! I forgot about this one

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[RASanders]

If the distance from the ATS to the panels is greater than the tap-rule allowance, as some have suggested it might be; isn't it possible you could/should install OCPD breakers right there (outside), or at least within the distance allowed?
That would seem to also allow you to ensure that you have load-side lugs rated for parallel conductors to serve each of the panels, which could then be Main Lug Only.

 

[electrofelon]

Not specifically a code issue, but a "best practice" suggestion: when you come out of the ground, like the conductors feeding the line side of the meter, put a loop, S bend, or even just a little zig zag in your conductor so they have some play so the expansion coupling can work. An expansion coupling isn't much good if the conductor can't move.

Are the nipples dropping down from the trough to the panels over 2 ft? They look like they are longer than that, and if so derating would be an issue.

 

[busman]

Something I haven't seen mentioned yet is the length of conductors of each parallel set of conductors - the ones between the meter socket and the main breaker. The "inside" run is shorter therefore has less resistance. Doesn't seem it would be very significant but the reason you are supposed to keep them the same length is so they have as close as possible to same resistance and that will help make current divide equally. If there is enough difference this can result in one conductor being overloaded and the other one being lightly loaded when the draw is high. On a dwelling and depending on demand situations this maybe wouldn't happen very often.

I think you meant this, but it's not the length that matters, but the proportional length difference between parallel conductors.

Mark

 

[busman]

Not specifically a code issue, but a "best practice" suggestion: when you come out of the ground, like the conductors feeding the line side of the meter, put a loop, S bend, or even just a little zig zag in your conductor so they have some play so the expansion coupling can work. An expansion coupling isn't much good if the conductor can't move.

Are the nipples dropping down from the trough to the panels over 2 ft? They look like they are longer than that, and if so derating would be an issue.

Using the panel width, which should be 14" (approximately), the nipples are over 24", so derating would apply. There is also a chance that ANY of those conduits are over the 40% limit for conduit fill.

Mark