Splice and Tap UG Service

[mkgrady]

Customer has an underground service feeding his house. The service lateral is about 200 feet long. He is going to build a barn and the UG service runs under the corner of where he will build it, so the service lateral must be moved. I'd say the corner of the building would cover about 8 feet of the existing cable. The new barn location is about the mid point of the run. The service lateral is direct buried 4/0 aluminum cable. Owner says it's 18 inches deep. I think it should have been 24" to meet code but I hope that is not an issue.

I'm thinking of installing two handholes a few feet back from where the foundation will be excavated, and running new cable around the corner of the building. I'll keep the cable several feet away from the new structure and bury it at least 2 feet deep. Splices will be made in each handhole to complete the circuit. I'll ask the Poco to shut it down during the excavation, trenching, cable laying, splicing and inspection which will take all day.

He also wants power in the new barn. Just a few lights, receptacles, maybe a welder, maybe a compressor. I'm thinking a 100 amp service to the barn but most of the time it will draw nothing at all. Would you expect the Poco would want a new UG lateral back to the pole? Or would you expect them to allow a tap into the handhole for a service. Customer doesn't want to dig back to the riser pole because he will likely dig into his existing service.

I'll discuss both issues with the Poco (Nstar) but thought I'd run it by you guys and gals first. Any feedback?

And last but not least, he wants to put a generator outside the barn to feed the house during outages. He figures he can utilize the existing cables that feed the house that run right by the barn. I told him those cables would not make his generator installation any easier and to trench a seperate run for that. I think he is just going to skip the generator as part of this project. I guess if money were no object to him (I don't know) I could put a 200 amp transfer switch in the barn and size the generator for the full house load but it seems pretty complicated and I'm not sure what the Poco would say about it.

Sorry for such a long post. Thanks for any input. Mike

 

[augie47]

does the underground lateral belong to POCO or the customer ?
where is it metered ?

 

[Smart $]

First you need to determine whether the existing lateral is of a size adequate to carry both the house and the barn. You need to do a service calculation, and in addition keep in mind voltage drop.

Additionally, where is the service point... i.e. who owns the service lateral? If the customer does, you "technically" don't need a poco blessing to splice and tap the lateral.... but a blessing may get the power turned back on

 

[480sparky]

If the conductor is sized for an exisitng service, adding another service could overload it as there's no fuses or breakers protecting it.

 

[mkgrady]

does the underground lateral belong to POCO or the customer ?
where is it metered ?

According to the customer he owns the lateral, but the meter is at the house, not on the riser pole, so I'm not sure who really owns it.

First you need to determine whether the existing lateral is of a size adequate to carry both the house and the barn. You need to do a service calculation, and in addition keep in mind voltage drop.

Additionally, where is the service point... i.e. who owns the service lateral? If the customer does, you "technically" don't need a poco blessing to splice and tap the lateral.... but a blessing may get the power turned back on

I'll do the calc but the service to the house appears to be oversized. I expect the calc for the house would be just north of 100 amps. If I have to go to a larger service lateral I'm certain the customer will just install lights in the barn and skip any other loads. He will however still want to tap the handhole or run to the riser to get power. I suggested 100 amp to the barn because it's not going to cost him any more than something smaller.

If the conductor is sized for an exisitng service, adding another service could overload it as there's no fuses or breakers protecting it.

Right, but I think a service calculation will check that out. I do wonder though what would keep the SE cable from overloading if the house main was 200 and the barn was 100. Maybe I could change the house main to 150.

The only thing the customer is certain of is that he doesn't want the house to feed the barn because that trench would really disturb his landscaping and brick walks.

 

[JWCELECTRIC]

MK,

Reroute the existing service to a new service setup in the barn. New meter,MCB, ATS, Generator all located in the barn. Then run a new feeder to the house which will become a sub panel (seperate netrls & grnds). From the ATS in the barn run cable into wireway that will feed a panel in the barn, then run another set from wireway to 200a breaker that will feed the house. Utilize the handholes as discribed in the opening.

- JWC

 

[mkgrady]

MK,

Reroute the existing service to a new service setup in the barn. New meter,MCB, ATS, Generator all located in the barn. Then run a new feeder to the house which will become a sub panel (seperate netrls & grnds). From the ATS in the barn run cable into wireway that will feed a panel in the barn, then run another set from wireway to 200a breaker that will feed the house. Utilize the handholes as discribed in the opening.

- JWC

Thanks, that would work great but he doesn't want to trench to the house. Too much invested in landscaping. But let's assume I could talk him into it. Would I have to install a generator that could handle the full load of the house? That's a pretty big generator. I'm guessing 20-30 KW. I've never priced one that big. I assume they are big money? He has no natural gas , so propane would have to do it. I'd love to do the job that way but it sounds very expensive.

 

[JWCELECTRIC]

Reuse existing UG conduit, attach the new 4/0 to existing cable, and hire the donkey from other thread for pulling

 

[augie47]

My first thought was along JWC's line by feeding the house from the barn, but if you are under the '08 Code, that may be a problem unless you have conduit or the required EGC.
Your first stop is definitely POCO. They are funny about things happening ahead pf their meter o
With their permission a tap box in the existing sounds like the best idea for now unless you can easily make the house a 4 wire supply, then I would think about JWC's route and put the service disconnect, ATS, generator etc at the barn with a feeder to the house.
If you are not under '08 and the can meet the applicable rules of 250.32, then if the existing service to the hosue is 3 wire you can still feed by way of the barn.

 

[Smart $]

My first thought was along JWC's line by feeding the house from the barn, but if you are under the '08 Code, that may be a problem unless you have conduit or the required EGC.
Your first stop is definitely POCO. They are funny about things happening ahead pf their meter o
With their permission a tap box in the existing sounds like the best idea for now unless you can easily make the house a 4 wire supply, then I would think about JWC's route and put the service disconnect, ATS, generator etc at the barn with a feeder to the house.
If you are not under '08 and the can meet the applicable rules of 250.32, then if the existing service to the hosue is 3 wire you can still feed by way of the barn.

Question: Is it possible to place a service-rated ATS ahead of a service disconnect?

If yes, I was thinking about rerouting the lateral to the barn, where the ATS would be located, and run the output through a splice/tap box and on to the house (i.e still a service lateral and not a feeder). The barn could be tapped in at the box to new meter and its own service disconnect.

 

[mkgrady]

Reuse existing UG conduit, attach the new 4/0 to existing cable, and hire the donkey from other thread for pulling

There is no conduit. Just direct buried cable.

My first thought was along JWC's line by feeding the house from the barn, but if you are under the '08 Code, that may be a problem unless you have conduit or the required EGC.
Your first stop is definitely POCO. They are funny about things happening ahead pf their meter o
With their permission a tap box in the existing sounds like the best idea for now unless you can easily make the house a 4 wire supply, then I would think about JWC's route and put the service disconnect, ATS, generator etc at the barn with a feeder to the house.
If you are not under '08 and the can meet the applicable rules of 250.32, then if the existing service to the hosue is 3 wire you can still feed by way of the barn.

2008 code applies. If it were not for the EGC being required I might be able to sell the generator upgrade. Because of it, I think all I'm gonna install is a splice in the handhole and a service to the barn.

But it makes me wonder, If I splce in the handhole and feed two services, how would it hurt anything to have the service feeding the house be run through a transfer switch at the barn? I guess the answer is that 08 would require the fourth conductor. But how is that any safer?

 

[480sparky]

If trenching is not an option, what about boring?

 

[mkgrady]

If trenching is not an option, what about boring?

I guess boring could be done but it seems like one more complexity (cost) that will likely put the brakes on the generator upgrade.

 

[Smart $]

But it makes me wonder, If I splce in the handhole and feed two services, how would it hurt anything to have the service feeding the house be run through a transfer switch at the barn? I guess the answer is that 08 would require the fourth conductor. But how is that any safer?

A slight twist to the question I asked

The only difference would be the tap for the barn service would be ahead of the transfer switch.

PS: A transfer switch without integral feeder OCPD's (or with basic disconnect switches) cannot be considered a service/SDS disconnect (unless ocp is placed immediately adjacent thereto).

 

[mkgrady]

A slight twist to the question I asked

The only difference would be the tap for the barn service would be ahead of the transfer switch.

PS: A transfer switch without integral feeder OCPD's (or with basic disconnect switches) cannot be considered a service/SDS disconnect (unless ocp is placed immediately adjacent thereto).

A tap for the barn service before a transfer switch for the house isn't a problem is it?

I could put the OCP right next to the transfer switch but I take it the seperate EGC would still be required going to the house?

 

[Smart $]

A tap for the barn service before a transfer switch for the house isn't a problem is it?

Shouldn't be... meaning I cannot think of any code prohibiting it.

I could put the OCP right next to the transfer switch but I take it the seperate EGC would still be required going to the house?

If there is no ocpd for the house at the transfer switch, you would not need an EGC to the house.

 

[augie47]

Shouldn't be... meaning I cannot think of any code prohibiting it.


If there is no ocpd for the house at the transfer switch, you would not need an EGC to the house.

He would have to have OCP ahead of the transfter switch. If the TS is at the barn. he would have to have the 4th wire. If the TS is at the house
he would only need it after the OCP, correct ?

 

[Smart $]

He would have to have OCP ahead of the transfter switch. If the TS is at the barn. he would have to have the 4th wire. If the TS is at the house
he would only need it after the OCP, correct ?

Fourth wire needed after service disconnect/OCP any way you go about it.

But what code requires an OCP ahead of a service-rated TS?

 

[hurk27]

A tap for the barn service before a transfer switch for the house isn't a problem is it?

I could put the OCP right next to the transfer switch but I take it the seperate EGC would still be required going to the house?

Yea unfortunately a feeder to the house will require a EGC, if it was a trailer you could use the exception in 550.33(A) go figure

I have done a few installs like this using a 200/320 meter can with double lugs at the barn to feed the house from and treat the panel at the house as service equipment, as the house SEC's don't enter the barn they don't need any additional overload or disconnect at the barn, just run back into the ground from the load side of the meter to the house with the existing 3 service entrance conductors, then you wont need the meter at the house either, just use by pass clips or remove the meter. But like was said the only way I see a generator is a ATS at both locations with one generator, or a generator at each location.
I have gotten away from transferring single circuits as the labor involved seems to almost cost as much as when doing a whole house transfer. A 15-20kw Generic system with a 200 amp ATS is about $3-4K at Home Depot, and the home owner has the peace of mind they wont be running around flipping breakers or worring about running the air. but thats just my opinion:grin:

Edited to add: Check with the suppying utility, ours offers a Generator for the whole service, and wires it ahead of the meter, for an extra amount on the utility bill, and they wire it ahead of the service on their lines, so no NEC to comply with.

 

[augie47]

none..if its a service rated TS. But would not anything downsteam from a service rated TS need the neutral-ground seperated ?
I may be missing your point, but it seems if the TS is not at the house, whether it be a service rated T/S (requiring internal OCP) or one with seperate OCP ahead of it, the 4th wire would be needed to the house.