The underground cable from my house to the meter pole (main disconnect) was installed before I bought this property. They used 4 wire underground service entrance cable. Two black (hot), one White stripe (neutral), and one green (ground).
The green wire is connected to the ground buss bar in the house's panel, but they never connected it to anything in the meter pole main box. The house has it's own ground rods (2 of them), but I still think that green wire should be grounded in that meter pole box, not just left unconnected.
I can see why they did not connect it. There are no spare ground lugs (screws). I've been meaning to do something with this, and finally went to do this job after several years. But there is no place to connect it as far as the lugs. However, there is the thick (#6) bare copper wire that goes to the ground rod below that panel, and it's right where this green wire ends inside that box.
My thought is to just put a split bolt around that bare copper wire and put the stripped end of the green wire into that split bolt too.
But two questions arise. I know this is a GOOD ground, but is this type of connection allowed by code. Also, the underground cable is aluminum, and the ground wire is copper. I dont like the idea of dissimilar metals, since they corrode. However I can get the split bolt that has a brass divider, that would separate these two metals.
Actually this is the only option I really have, other than just leaving it unconnected. (which is how it's been for years).
You're right. 3 wires, two are hot, one is neutral. The hots are fine. The neutral is connected to the same buss bar that the grounding system is connected.
Let me explain. This is a farm, where there is a main meter pole. The meter has a main disconnect panel under it. There are two pull out fuse blocks in there, each is 200A (400A service). I dont need half that amperage, but this was a once a large farm with all sorts of grain dryers and power consuming stuff. Now, I just run a small farm and dont need all that much power. But that old fuse panel is still there. I have two overhead triplex cables connected to one of these pull out fuses. They feed the barn and garage and other sheds. The house is connected via underground SE cable and is connected to the other pull out fuse. THe house and the garage and barn each have separate breaker panels each have their own MAIN breaker and each has their own grounding system.
Anyhow, getting back to that meter pole panel. The neutral and ground are bonded in that box. Thats normal. But the house has newer wiring and this there is that 4th wire (green wire) which does not exist in the overhead triplex cables to the other buildings.
When I moved here, the electric compamy inspected that panel before they would turn on the power. They said it was OK, even with that green wire NOT connected. So, I'm not really concerned about the code so much. But I still think that green wire should be connected to the ground on that end. (Mostly for lightning spikes).
In the house, there is a newer breaker panel, which has separate neutral buss bar and ground buss bar. So in the house they are separated and the green wire goes to the ground buss along with the house grounding system. However that green wire does nothing since it's not connected on the other end.
Back at the meter pole panel. Because there are 3 separate feeds and some very thick cables due to the 400A service. Therefore, there are no spare screws (lugs) for this green wire and none will accept another cable because they are not big enough to double up cables.
So, I'm back to either clamping it to the ground wire, or leaving it disconnected.
Like I said, the code is not all that important since the power company said things were OK. Even if it's a technical violation, I know it's not a hazard. I just think in the event of a lightning surge, the more grounding the better.
I'm mostly just concerned about connecting the aluminum cable to the copper one, regarding corrosion issues....
Use a cu/al rated lug to fasten the green wire to the 400 amp can. Use a bolt and nut thru the lug to a solid (no knockouts in the path and paint removed from contact area) part of the panel enclosure.
It should be bonded to the neutral in the enclosure where the main disconnect resides. Is there a way to bolt another lug to the ground bar in the main disconnect?
You are right. He clarified his post to say the neutral and ground were split in the house panel and in that case the ground wire should go straight from the ground bus in the panel to the neutral/ground bus in the main disconnect enclosure where the main bonding jumper resides. Up until 99 or 02 it was legal to feed panels in separate buildings with 3 wire and create a new neutral ground bonding jumper there.
You're right. 3 wires, two are hot, one is neutral. The hots are fine. The neutral is connected to the same buss bar that the grounding system is connected.
Let me explain. This is a farm, where there is a main meter pole. The meter has a main disconnect panel under it. There are two pull out fuse blocks in there, each is 200A (400A service). I dont need half that amperage, but this was a once a large farm with all sorts of grain dryers and power consuming stuff. Now, I just run a small farm and dont need all that much power. But that old fuse panel is still there. I have two overhead triplex cables connected to one of these pull out fuses. They feed the barn and garage and other sheds. The house is connected via underground SE cable and is connected to the other pull out fuse. THe house and the garage and barn each have separate breaker panels each have their own MAIN breaker and each has their own grounding system.
****************************************************************** What you have here is 200 Amp. 220 single phase supply service not 400. because one wire carry 200a. and the other 200a. that is not 400 amp. service. This service require number 3/0 wire conduit 2.1/2". If your property does not need of that power suggestion is reduce size of fuses to 100A. Which in most cases for normal house is sufficient enough. Ground Green or bare wires must be connected together and grounded on both sides. Caution: if this wires are not grounded on both sides at poll and at house it is possible to have induced Voltage into the wire/cable (potential) be "careful" If there are no connecting place to tight together you can drill small hole and use small bolt with nuts to secure tighter. Remember you are working next to Electricity and Electricity dose not discriminate.
*****************************************************************
Anyhow, getting back to that meter pole panel. The neutral and ground are bonded in that box. Thats normal. But the house has newer wiring and this there is that 4th wire (green wire) which does not exist in the overhead triplex cables to the other buildings.
When I moved here, the electric compamy inspected that panel before they would turn on the power. They said it was OK, even with that green wire NOT connected. So, I'm not really concerned about the code so much. But I still think that green wire should be connected to the ground on that end. (Mostly for lightning spikes).
In the house, there is a newer breaker panel, which has separate neutral buss bar and ground buss bar. So in the house they are separated and the green wire goes to the ground buss along with the house grounding system. However that green wire does nothing since it's not connected on the other end.
Back at the meter pole panel. Because there are 3 separate feeds and some very thick cables due to the 400A service. Therefore, there are no spare screws (lugs) for this green wire and none will accept another cable because they are not big enough to double up cables.
So, I'm back to either clamping it to the ground wire, or leaving it disconnected.
Like I said, the code is not all that important since the power company said things were OK. Even if it's a technical violation, I know it's not a hazard. I just think in the event of a lightning surge, the more grounding the better.
I'm mostly just concerned about connecting the aluminum cable to the copper one, regarding corrosion issues....
The neutral must be bonded to the ground at the "main panel" and must not be bonded at the "sub panels" IIRTCC. According to that rule, the ground at the pole should be connected to the house ground cable, and to ground cables for all other buildings if the pole disconnect is considered the "main panel"
However, if the pole disconnect is not the main panel, then the ground and neutral would not be bonded at the post, and would be bonded at each "main panel" in each outbuilding.
Not sure how this is considered in code - anyone out there know "for sure"?
No, he has a 400 amp 240 volt single phase service, with 2 200 amp
240 volt fused disconnects - both of which can handle 200 amps of 240 volt loads. That is 200 amps line to line on each disconnect - or 400 amps line to line on the main feed.
If the house has a 200 amp panel, he needs the 200 amp disconnect and
200 amo fuses on that "disconnect" - and fusing the other "disconnect" at 200 amps is no problem if he has 200 amp rated triplex feeding the outbuildings. Otherwise, the triplex to each building needs to be rated at least for the capacity of the main breaker in the building in question.
Ground loops are not the issue and nothing on the line side of a GFCI should trip it. The issue with "regrounding the neutral" is you are going to impose some current on the grounding conductor and the voltage will rise in reference to ground level. This will be mitigated when you actually create another ground reference in the sub panel in a second building but then you are really not using a separate ground at all. They still see it as "Objectionable current on the grounding conductor" so you do not connect at both ends and in the case of the line side (power company service conductors), you don't have a grounding conductor at all (just 3 wires)
For most of the life of the NEC they treated a second building as a separate service in regard to the grounding but they chipped away at that idea until it disappeared. Now it is just like a sub panel inside the same building, 4 wire feeder and an isolated neutral. They just kept the ground rod requirement to create a fresh ground reference for the equipment grounding bus bar.
The pole is where the service disconnect resides and you are right. he needs the green wire grounded there. The fault path for anything in the house is now using earth for a conductor. It might work in a lot of places but it is not legal or safe.
No, he has a 400 amp 240 volt single phase service, with 2 200 amp
240 volt fused disconnects - both of which can handle 200 amps of 240 volt loads. That is 200 amps line to line on each disconnect - or 400 amps line to line on the main feed.
If the house has a 200 amp panel, he needs the 200 amp disconnect and OR 200 Amp. Distribution panel with circuit barkers as needed equal to =
I'm not adding each wire. I'm adding the two separate fused disconnects on the one service. He has two 200A disconnects. I can show you new construction here, large homes that have two 150A panels, right next to each other. Each has a 150A breaker, the service is 300A. By his description, it sounds like that is what he has. It's apparently a house plus a farm.
I'm not adding each wire. I'm adding the two separate fused disconnects on the one service. He has two 200A disconnects. I can show you new construction here, large homes that have two 150A panels, right next to each other. Each has a 150A breaker, the service is 300A. By his description, it sounds like that is what he has. It's apparently a house plus a farm.
***************************************************************** A___(__/ __)______ Hot 200 amp. B___(__/ __)______ Hot 200 amp. single phase 200 amp service (not 400) C_____________ Neu. Eqv. to D_____________ Grd. #8 r 6
It is not how many disconnect or how many panels, it is what is supply, what size of line coming down the poll or what size transformer is supplying source, if disconnect is rated at 200 Amp. I don't care if it two fuses or three or one? it is still 200 amp service not 400.
I'm willing to let Gfre settle the issue. He's an electrical inspector. It's not "a disconnect". It's TWO 200A disconnects connected to the same service. I say that's a 400A service, like the OP says. If you have two 200A disconnects on the same service, you could pull 400A without them tripping. Seems that would be a bad idea, with a service only rated for 200A.
Sounds right to me. Those old farm "maypoles" were popular ways to get power around the spread and generally once the service was set, nobody ever looked at it again since farmers usually can avoid most of the permitting process. I suppose pulling a permit for a house may have brought the kind of scrutiny that got him the 4 wire feeder but that was really only a requirement fairly recently. (99 or 02 maybe) It is a shame they did not connect the EGC to anything. It defeats the purpose and exposes him to a hazard. There is no fault path to trip a breaker other than the earth. Screwing a lug into the can at the disconnect is better than nothing (scrape off a little paint and use a star washer) but the right way is to connect directly to the bus bar, even if that means he has to add another bar, swing over one of the existing and add a jumper. Using a split bolt, connecting to the ground electrode conductor is legal too. Just be sure it is the duplex type with the interposer if you are mixing cu and al.
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