Extending SE Cable

[mkgrady]

I'm installing a whole house standby generator on a residence. The ATS will now become the service disconnect and the existing main breaker panel will become a sub panel. I will need a longer SE cable from the meter to the ATS than what is existing. The existing panel is in the basement just below the outside meter.

On this job it will be difficult to replace the SE cable (underground service entrance) so I'm planning to extend it a couple of feet with a splice and a junction box. I have never extended an SE cable before and I'm wondering what my options are. The simplest way seems to be to use a PVC junction box and SE cable connectors to attach the cables to the box. I won't have to ground the box. I have no idea how to ground the metal connectors but it's hard to imagine how they would become energized.

My first thought was to use a metal box but then I thought about how the box would get grounded. Obviously there isn't an equipment ground in the SE cable and connecting a metal box to the neutral seems wrong anywhere but the main disconnect.

As an alternative, what would be wrong with splicing onto the SE cable conductors within the existing main breaker service panel. They could be made long enough to run through a short nipple and terminate at the ATS and then run back through the same nipple from the load terminals of the ATS.

Any code violations in either plan?

 

[LarryFine]

If you're talking about extending the load side of the meter, replace the existing cable with a longer, unbroken length.

 

[hbiss]

The simplest way seems to be to use a PVC junction box and SE cable connectors to attach the cables to the box. I won't have to ground the box. I have no idea how to ground the metal connectors but it's hard to imagine how they would become energized.

My first thought was to use a metal box but then I thought about how the box would get grounded. Obviously there isn't an equipment ground in the SE cable and connecting a metal box to the neutral seems wrong anywhere but the main disconnect.

Not agreeing that splicing is the correct way, (I agree with Larry) but what you are saying about how to do it isn't correct either. Metallic SE connectors do have to be bonded and a PVC box isn't the way to go. Use a metal box and think about how the meter pan is grounded to the neutral if you think the only place to bond to it is the main panel.

-Hal

 

[petersonra]

any reason you can't just leave it where it is now and just extend it from there?

 

[mkgrady]

If you're talking about extending the load side of the meter, replace the existing cable with a longer, unbroken length.

Yes that is what I mean and I have replaced the cable many times in the past but getting the the connector on the back of this meter socket might be difficult enough to seek alternative ways to get the job done. If it violates the code I won’t splice it but that is the question.

 

[mkgrady]

Not agreeing that splicing is the correct way, (I agree with Larry) but what you are saying about how to do it isn't correct either. Metallic SE connectors do have to be bonded and a PVC box isn't the way to go. Use a metal box and think about how the meter pan is grounded to the neutral if you think the only place to bond to it is the main panel.

-Hal

So I would just use bonding bushings and bond the connectors and the metal box to the neutral. I thought the only places this could be done were at the service disconnect and the meter enclosure. I assumed somewhere in between would not be allowed. I also agree with Larry that replacing with a longer SE cable is better but I’m looking for code compliant alternatives.

 

[mkgrady]

any reason you can't just leave it where it is now and just extend it from there?

I’m not sure what you are asking. It sounds like the last idea in my original post but I’m not sure if that is what you mean

 

[augie47]

Before you go to the trouble it might be a good idea to run it by your inspector.
It sound like your existing panel may now be a sub-panel off your T/S disconnect,
A 4 conductor SER might be required.

 

[mkgrady]

Before you go to the trouble it might be a good idea to run it by your inspector.
It sound like your existing panel may now be a sub-panel off your T/S disconnect,
A 4 conductor SER might be required.

No. The existing panel is the main service panel. It is fed with SE cable that is not long enough to reach a new ATS. I’m going to covert the existing main panel to a sub panel down stream of a new ATS.

I will either run a new SE cable from the meter to the ATS or I will extend it with a splice. I’m just trying to determine if my ideas are code compliant.

It has been pointed out that splicing it in a pvc box will not be compliant but it seems a metal box will comply. It also seems that if SE connectors were non-metallic I could use a pvc box for the splice but I’m not aware of any.

 

[Carultch]

No. The existing panel is the main service panel. It is fed with SE cable that is not long enough to reach a new ATS. I’m going to covert the existing main panel to a sub panel down stream of a new ATS.

If the existing panel is going to become a subpanel, the neutral and ground that supply it become separate conductors, and the neutral-ground bond takes place in an upstream service disconnect. The grounds and neutrals in the subpanel get isolated from each other, such that only the grounds get bonded to the housing.

This means that the SEU cable would be replaced with SER cable, as SER cable has a separate conductor for neutral and for ground. It has within it, a bare ground and a neutral insulated just like the ungrounded conductors and marked with a white stripe. SEU by contrast, is two insulated wires and a distributed bare wire, with that distributed bare wire for the ground and neutral together, but only on the line-side of the service disconnect. If you had an application only requiring two insulated wires, you could use the distributed bare in SEU cable as the ground. But if the distributed bare in the SEU cable is going to be used as a neutral, the SEU cable needs to be on the line side of the service disconnect.

 

[LarryFine]

Can you mount the ATS inside, nippled to the existing panel, and lengthen the conductors inside? You wouldn't even have to reroute the existing neutral to the ATS.

Added: Carultch is correct that, in any case, the existing panel must be re-wired as a sub-panel, removing the bonding jumper, and separating the grounds and neutrals.

You're also technically supposed to replace any 3-wire major appliance circuits, sockets, and plugs and cords with 4-wire.

 

[LarryFine]

And, I'm wrong about leaving the existing neutral in the existing panel. It has to be re-routed to the ATS, and the return neutral must be insulated. The existing panel should be grounded by an EGC, and not the neutral.

Doing this is much easier on services that already have an outside main, a 4-wire feeder, and an un-bonded panel. The last two ATS installations I did were like this. I replaced one disco with the ATS, and nippled to the disco with the other.

 

[mkgrady]

Can you mount the ATS inside, nippled to the existing panel, and lengthen the conductors inside? You wouldn't even have to reroute the existing neutral to the ATS.

Added: Carultch is correct that, in any case, the existing panel must be re-wired as a sub-panel, removing the bonding jumper, and separating the grounds and neutrals.

You're also technically supposed to replace any 3-wire major appliance circuits, sockets, and plugs and cords with 4-wire.
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The ats is going to be installed right next to the existing main breaker panel in the basement. I wasn’t sure if service conductors could be extended and run through the existing main panel. Just seems like it needs to run directly to the new service disconnect which will be the ats. This would be code compliant?

Yes I’m aware that the old service panel is now going to be a subpanel and that older three wire circuits if they exist must be changed to four wire.

 

[mkgrady]

And, I'm wrong about leaving the existing neutral in the existing panel. It has to be re-routed to the ATS, and the return neutral must be insulated. The existing panel should be grounded by an EGC, and not the neutral.

Doing this is much easier on services that already have an outside main, a 4-wire feeder, and an un-bonded panel. The last two ATS installations I did were like this. I replaced one disco with the ATS, and nippled to the disco with the other.

Yes I caught that about the neutral having to stay with the hot conductors. If I had a main breaker at the meter and four conductors coming in this job would be much simpler and I would not be asking about splicing.

 

[Eddie702]

Why can't you come out the side of the meter socket with a new pipe (or se cable) and penetrate the house in a new location to feed the ATS. The go fro the ATS to the existing panel inside the building. Abandon the old SE cable to existing panel feed

 

[LarryFine]

Why can't you come out the side of the meter socket with a new pipe (or se cable) and penetrate the house in a new location to feed the ATS. The go fro the ATS to the existing panel inside the building. Abandon the old SE cable to existing panel feed

That could work for either inside or outside mounting of the ATS. The existing SE cable will be useless in the panel.

 

[mkgrady]

Why can't you come out the side of the meter socket with a new pipe (or se cable) and penetrate the house in a new location to feed the ATS. The go fro the ATS to the existing panel inside the building. Abandon the old SE cable to existing panel feed

I like the idea. Thanks for that. It might work. I’ll have to see if there is room next to the meter. It is a real crowded space.

Is anybody willing to agree that my original idea about lengthening the SEU cable with a splice is code compliant or not?

 

[LarryFine]

Is anybody willing to agree that my original idea about lengthening the SEU cable with a splice is code compliant or not?

It is. It wasn't always, but they changed it a few codes ago.