splicing service entrance cable

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  #1  
Old 09-15-12, 02:09 PM
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splicing service entrance cable

I am installing a generator with an automatic transfer switch. To do this I have to move the USE service entrance cable from the lugs on the main panel, to the lugs on the adjacent transfer switch. The cable comes into the panel from the back and it is not long enough to reach the transfer switch. Is it possible to splice the 0000 aluminum USE inside the panel so I have a long enough length to reach the switch? If so, what type of connector would I use? Thanks in advance, John.
 
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  #2  
Old 09-15-12, 02:45 PM
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I would not splice the service entrance cable, specially aluminium wire.
What is the amp rating of the transfer switch?
What is the amp rating of the generator?
It sounds like you have a 200 amp main panel? To "transfer" the entire house to a emergency generator would requrie a large generator. They will overload and burn up.
Normally you would install a second panel "emergency panel". Supply power to the transfer switch from a 2 pole breaker in the house panel. Also supply power to the transfer switch from the generator. The transfer switch would now supply power the the "emergency panel." Splice out the need circuits from the house panel, ie.. heating, well, sump pump, refirgerator, some lighting, and extend them to the "emergency panel." Would not recomend running the TV's from the generator.
 
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Old 09-15-12, 02:56 PM
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The transfer switch is a generac "smart switch" rated at 200 amps. The generator delivers 60 amps, but the entire panel is energized with designated loads being shed when necessary so as not to overload the generator. Installation calls for the service entrance cables be moved to the switch. I hope I am making this understandable.
 
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Old 09-15-12, 04:06 PM
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Is it possible to splice the 0000 aluminum USE inside the panel so I have a long enough length to reach the switch? If so, what type of connector would I use?
Yes, you can make splices inside a service panel that is closed (covered) during normal operation.

The standard connector for splicing 4/0AWG cables is a barrel connector, such as this 3Mô Connector CI-4/0, 4/0 AWG stranded, Connector. Those require a crimp tool for installation. They should be available at a local supply house.

To avoid having to crimp the connectors onto the cable, shearbolt connectors such as the 3Mô Shearbolt Connector QCI Series 4/0-600 have been developed. My personal favorite is a clear tap, such as the Ilsco ClearChoice. The splice is made using an Allan wrench, and the connector, and the splice, are inside a flexible insulating cover. You cut and strip the cable, phase-tag it, stick the stripped ends through the cover into the holes made to receive them, crank down with your Allan key, and you're done. I spliced all three hot phases and the GEC, to feed three separate panels, in about 20 minutes one day, and it was ready to energize at that moment.

I would stay with the 4/0 Al for the extension, if the feed lugs on your ATS will accept that. If not, just make sure you buy splice connectors that will accept both sizes. IIRC, the clear taps help reduce or eliminate galvanic corrosion because each conductor is attached separately, but I know we poured a lot of the black anti-corrosion gunk on those connections I made that day, because it was one of the few jobs we ever pulled in Aluminum.

Basically, I would just tell the counter person at the supply house what I was doing and see what they came up with. But I thought you might enjoy seeing some options before you went shopping.

Who's going to kill the power on change-over day?
 

Last edited by Nashkat1; 09-16-12 at 04:44 PM. Reason: to add a missing link
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Old 09-15-12, 04:14 PM
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If you have installed automatic load shedding relays, and the load shedding controller is set to match the capacity of the generator, then the full-load transfer switch is acceptable per 702.5(B)(2).

Yes there are splice blocks available for 4/0 aluminum, and you can make the splice inside the panel. However a better way of doing it (if feasible) is to move the panel over a little bit, and place the transfer switch so that the SE comes directly into it. This of course is contingent on your panel being surface mounted and there being enough slack in your branch circuit cables to do so.
 
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Old 09-15-12, 04:29 PM
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Thanks for all the help. I like the idea of moving the panel a bit. I don't think there is enough slack in the branch wires but I will take a good look tomorrow. We are going to pull the meter on change over day.
 
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Old 09-15-12, 04:53 PM
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Is the ATS service entrance rated? Does it have a 200 amp main breaker in it? If not, you'll need a 200 amp rated service switch or circuit breaker that is marked "Suitable for Service Entrance". If it is suitable and so marked and if it does have a 200 amp main breaker in it, your plan will give you a very congested main panel. It would also make your existing panel a subpanel and that requires that the neutral and ground conductors be separated with neutral bar being isolated from the panel box. You may have to add a separate ground bar. The service neutral conductor would now be grounded at the service entrance switch which would now be in the ATS. You'll also have to run 4 wires between the ATS and the existing panel; 2 hots, 1 neutral and 1 ground.
 
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Old 09-15-12, 07:04 PM
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I like the idea of moving the panel a bit. I don't think there is enough slack in the branch wires but I will take a good look tomorrow.
If you're willing to take some pictures of what you have now and post them here, we can look at it with you. See How To Include Pictures.

I agree that you're going to be crowding a lot into the top of your existing panel if you try to do everything there. Installing a splice box or two, for the entrance cables or the branch circuit cables, for example, might be a help. Feeding directly into the ATS will help a lot, if you can make that happen.
 
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Old 09-15-12, 07:22 PM
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If the ATS is rated for outdoor use, you can put it outside, directly below the meter.
 
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Old 09-16-12, 03:45 AM
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Yes it is rated for outdoor use. I will certainly see if mounting it outside will work for this installation. The only problem is that the service runs underground from the meter to the main panel. As CasualJoe points out I would need a separate ground wire from the transfer switch to the panel. There is no room in the existing conduit, but I do have a spare running along side of it. Can I run this ground wire in the spare conduit? Thanks, John
 

Last edited by blockmanjohn; 09-16-12 at 04:36 AM.
  #11  
Old 09-16-12, 05:38 AM
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The only problem is that the service runs underground from the meter to the main panel
That may not be a problem at all. Does the conduit come up out of the ground surface mounted for 4 or 5 feet and then to an LB fitting to go through the wall into the back of the panel? If so, this might be a good place to interrupt the conduit and install the ATS. A picture of this area as well as a picture of the open panel may be helpful.
 
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Old 09-16-12, 12:59 PM
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No, the conduit runs underground and through the basement wall directly into the back of the panel. I have a picture of the open panel and will post it as soon as I can figure out how to do it.
 
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Old 09-16-12, 01:15 PM
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the conduit runs underground and through the basement wall directly into the back of the panel.
How much space is there between the bottom of the meter base and the ground?
 
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Old 09-16-12, 01:20 PM
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Attachment 3454
This is my panel. There is about 4 feet between the bottom of the meter pan and the ground. I plan to move the cables on the left of the panel and mount the transfer switch there.
 
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Old 09-16-12, 03:51 PM
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The link didn't work. Maybe including the picture in the post would work better.

But anyway... You have +4 feet between the meter base and the ground. Your transfer switch is rated for mounting outside, it's an automatic switch, and the generator will be outside -- but it sounds like you're planning to move stuff around and mount the ATS inside. How does that help you?
 
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Old 09-16-12, 04:13 PM
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Maybe this will work.
I don't want to place the transfer switch outside by the meter because running another underground conduit to the generator from the switch would be a real problem.
 
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Old 09-16-12, 05:32 PM
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Yes, it's visible. Now, let me see if...

Name:  main panel 2.jpg
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yes - it's right side up now, I think.

Is that a poured foundation wall that the panel is mounted on? If so, how are you planning to bring the generator feed to this location?

And when you say
I don't want to place the transfer switch outside by the meter because running another underground conduit to the generator from the switch would be a real problem.
I'm wondering how far away you're planning on mounting the generator. It's not going to be right next to the service entrance?

You'll also need to run control wiring from the ATS, at least, to the generator, won't you?
 
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Old 09-16-12, 07:20 PM
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I don't know where the knockouts are on the ATS, but what if you moved the panel over 6" (and up a few inches too since all the circuits are coming in from the top). Then mount the ATS over where the SE wires come in. Add a short nipple between the two, and you should be good to go. You'll have to add to the plywood panel, and shift all the coax over, but IMO, the coax is all too close to the panel anyway and may be picking up stray signals. (not a code issue though)
 
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Old 09-16-12, 07:43 PM
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Thanks for your attention to detail. I guess I need to explain all of my limited thinking on this.
Yes it is a poured foundation. The generator will be about 40 feet from the basement wall, but in a different direction than the meter. There is a very straight and unobstructed path to dig a trench for the ,as you point out, two conduits for power and control wires to be buried from the generator to the basement wall. To trench from the meter to the generator I would have to dig up my driveway and go around a shed.
At the end of the trench from the generator to the basement I would come up and through the house box beam. This point is directly above my panel.
It seems a lot easier to do the simple trench and splice the service entrance wires in the panel, and place the transfer switch next to the panel.
Does this make any sense? I am trying to make things as clear as I can.

Zorfdt, Just out of view at the right side of the photo is a vertical waste line. I can't put the ATS to the right without moving it.
 

Last edited by blockmanjohn; 09-16-12 at 08:01 PM.
  #20  
Old 09-16-12, 08:22 PM
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Thanks for the clarification.

When you get to the end of the trench, directly above your panel, where are you relative to the meter base and the existing conduit from the meter to the panel? Could you connect both feeds in and the one feed out there?
 
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Old 09-16-12, 08:36 PM
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From the end of the trench at the basement wall it is about 35 feet to the meter pan. It would be very difficult to dig a trench between the two. I think this is the answer to your question. Please correct me if I am wrong.
 
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Old 09-17-12, 01:04 PM
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I'm confused. Could you perhaps post some pictures of where everything is?
 
  #23  
Old 09-17-12, 02:50 PM
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Well it looks like our local etectrical inspector solved the problem for me. He wasn't happy about splicing the SEC in the panel. He suggested I pull a new, longer cable from the meter to the panel. He also added that it would be a good time to upgrade the 0000 aluminum to 00 copper. I don't like the added expense of 60 feet of copper, but it makes sense.

I want to thank every one for their thoughtful replies. This is a great forum. John
 
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Old 09-17-12, 03:03 PM
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There's nothing wrong with 4/0 aluminum, and there is nothing wrong with splicing the SE inside the panel. And you can call him out on that. He can not fail you for something that's legal.

You could actually probably make it work without splicing, since the SE comes in on the side rather than at the top. Is there a knockout in the side of the panel large enough for a 2" conduit connector? Or a "blank" space (a spot without 1/2" knockouts) where a hole could be drilled for one? If so, there looks like enough slack in the SE to go right out the side if you mount the ATS right there.

Edit: My bad, I missed that Zorfdt had already suggested something along those lines. How about if you move the panel to the RIGHT (bring the SE into the panel from the LEFT side back knockout), and mount the ATS on the left side doing the same idea? It would still be less movement than if you were to try bringing the SE right into the back of the ATS, and the panel should still clear the waste stack.
 
  #25  
Old 09-17-12, 03:23 PM
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I think the only problem with that is the neutral SE wire. If you look at the photo, it is only about 8 inches long. Not enough to get it where it needs to be in the ATS>
 
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Old 09-17-12, 03:30 PM
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Gotcha..

Got a model number or pic of the ATS? Usually they don't switch neutral, so the neutral would only have to go as far as a lug block inside the panel, it wouldn't have to go all the way to the switch contacts . If you use a short nipple, what you have might just be enough depending on the placement of the neutral lugs..

But again, there is nothing that says you can't splice it. Space-wise, one splice takes up less than three, and you could also splice it inside the ATS if you have enough to at least make it into the box.
 
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Old 09-17-12, 04:04 PM
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I think the only problem with that is the neutral SE wire. If you look at the photo, it is only about 8 inches long. Not enough to get it where it needs to be in the ATS.
Hmmmm... What if you moved the panel to the left and up? How far above the floor is the top of the main breaker in it now?

What I'm thinking is that if you could move it left far enough to let you mount the ATS over the SE feed, and up far enough to prevent having to splice the branch circuit cables, then you feed the generator power into it, feed out to the panel, and be done.

While splicing inside a closed panel is as legal as sunshine, splicing service entrance feeders is really frowned on. But it might beat pulling all new copper, especially if you only need to extend the neutral.
 
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Old 09-17-12, 04:07 PM
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I looked at the ATS schematic and the neutral lug is in the upper left side, no way to get my neutral there without a splice. I guess my options are a confrontation with the inspector, or buying some new SEC.
 
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