I’ll keep it as brief and to the point as possible. Couple neighbors and I are helping another neighbor get a new service entrance installed, replacing an existing, functioning service. Rotten post, obsolete meter base/breaker box, supplying about a 30 year old mobile home and well house. Direct burial to mobile and well house, 4 wire to mobile, 3 wire to well house. Typical well house, rat’s nest of wiring, with the ground being used to produce 120v circuits. We planned to establish a new ground at that location with ground rod, bonded well casing, and use the existing 3 wire for hot/hot/neutral. There are many boxes being replaced in this area with this situation, and the inspectors have never gone beyond the service entrance for inspection, allowing existing wiring to be hooked up assuming proper gauge/breaker, etc. This inspector has a neighbor open the buildings, is requiring an new 4 wire branch trenched in, went in the mobile, under the mobile, requiring smoke detectors, etc.
My question: Is establishing a separate ground a legitimate solution? Can anybody quote the appropriate code? This person doesn’t have a lot of money, and the trench is probably going to cross unknown water lines. Thanks in advance for all the expert information I know I am about to receive.
PS. the new service entrance was installed and everything new passed.
Edited 8/29/2009 11:49 pm ET by 082250
Replies
I will not comment on code issues, as i ignore the code everyday (rules for simpletons and to protect the insurance compnaies IMO). - ps, can see a thread hijack coming? <G>
What is of vital concern to you however, are ground currents to the well casing that will corrode pinholes thru the casing over 10 or 20 years, or even less.
On own well ( which, btw, I do use for a neutral, no 4th wire) made sure ( with a mA meter in the ground to WW connection to the casing) that I had less than 150 uA leakage current from house WW flowing, and monitor it every few months. Balanced 240 V loads are the key.
If you do not understand electrolysis issues, better follow the code - even the code will not protect the well casing in many instances due to parallel current flows.
Thanks for the comments, junkhound. Yes, I do understand electrolysis issues. The inspector is requiring the well casing bond, a relatively new requirement locally. My main concern is the 3 wire vs. 4 wire, which I also understand, but am trying to get it down to specific code, since this is what the inspector is citing. I've done a few of my own installations, with permits, passed, and this is the first inspector that has gone this far beyond what the permit was pulled for. In the meantime, the lady doesn't have power or water, and luckily, just the cat is there for now.
You're in Oregon? You can look at the State of Oregon electrical code online, at http://nfpaweb3.gvpi.net/rrserver/browser?title=/NFPAOR/OregonNEC2008 It appears they go by the 2008 NEC with some modifications. The section you need to look at is article 250, page 250.32. The code does require a separate ground wire for connections to a detached building.
I don't think upgrading the service has anything to do with requiring smoke detectors, but I assume the inspector is requiring they be added since he didn't see any when he went inside. It's a good idea though, especially in a mobile home - my sister and her husband died in a mobile home fire a few years ago and smoke detectors probably would have saved them. The battery operated ones are inexpensive, unless the inspector is going to require the hard wired type.
Edited 8/30/2009 11:24 am by Stuart
three wires for 220 if you have a 110 off that ciruit you need a netrual so four wire. if all was in pump house was 220 pump then three wires if there a light or 110 outlet, four wires.
Thanks for your references to the specific codes. I am aware that the current code requires the 4 wire branch circuit. When I have replaced service entrances on a couple of properties of my own served by fuse boxes, the inspector specifically told me I didn't need to upgrade any other wiring, and when he came for inspection, I offered access to the junction boxes that the old circuits were routed to, he said "I don't need to see that". He just inspected the new work. The owner has no issues with the smoke detectors, was just a bit PO'ed that the inspector found need to go in the mobile home without her permission, or presence. I will look up the codes you mentioned.
Your post brings up all manner of "red flags" that need to be addressed.
First of all, is sounds like you have a mobile home being powered from an RV-type pedestal. That's the first issue. Ordinarily you would have only a meter and a main disconnect on that post outside the trailer.
How large a service? Look at the trailer, In code terms, mobile homes are not homes - they're appliances. You need to look at the name tag for the trailer, and see what size service they specify. While a real house will often do just fine with a 100 amp service, many trailer require a 200 amp service.
Nor can you just lay the cord from the trailer atop the ground. You need to trench - at least 24" deep - to a spot under the trailer, then have a junction box there for making your connections. That junction box will need to be at least 8x8x4".
As for the well building, you need to do two things. First - and there's no getting around this - you have more than one circuit in that well house. So, that wire going to the well house is not a 'branch circuit,' it's a 'feeder.' That means it has to feed a panel (meaning it needs FOUR wires to it), and probably needs a disconnect on the outside of the building.
Second, since there is more than one circuiy, and this is a separate structure, you need a ground rod - in addition to the ground wire run with the feeder. Both the ground rod and the ground wire from the feeder will terminate on a separate ground buss; only neutrals connect to the neutral buss, and you DO NOT bond the neutral buss to the enclosure.
Help your neighbor? How noble of you. This mess didn't happen overnight, though - and there is no easy fix. Start digging.
The mobile home is a 200 amp service, by way of what they call a 'mobile home service entrance' here, not an RV pedestal. 200 A main, with a separate 60 A breaker for the well house. The new service entrance/meter base is also 200A with a separate breaker location on the hot side of the main specifically for a well, so the power can be shut off to the mobile without killing power for water. The inspector didn't have any issues with the new work or wires to the mobile. The panel we replaced was very common on mobile homes installed in this area 25 to 30 years ago. They all started failing (mostly burnt buss bars) about 10 years ago. The local lineman actually asked if he could have the internals (breakers), as he gets regular emergency calls, and apparently parts are no longer available. This lady's box was still functioning properly, she was just trying to stay ahead of problems. I've seen several of these replaced without replacing the 3 wire branch. And I've never seen a well house of that vintage in this area with a 4 wire. And the Poco won't hook up a new service without the green tag from the inspector. I know the lineman well and will ask if he has recently been seeing this requirement on rework.Thanks much for your info.
I appreciate the clarification ... let's just say I've had far too many encounters with RV's - mobile homes, and the park operators, that were disasters that I have become a bit jaded.
I've had a few encounters with mobile homes around here (which is why the other neighbors enlisted my help), and believe it or not, this is far from the worst. And on the worst ones, the people are generally looking for the easy way out. This lady wants it right and safe, and is willing to do what is necessary to accomplish that. Apparently, there are some local feuds I am not aware of, and one neighbor (not friendly to her) made a point of stopping to talk to the inspector while he was there. Coincidence????Thanks for your help and information.
08,
Well, considering just the wellhouse and not any potential problems with the mobile home, the 3-wire existing from the new service to the wellhouse are feeders and can be used as hot/hot/neutral (without a 4th ground wire) if the following conditions are all met:
* there is no 4th wire
* there are no other continuous metallic paths back to the service or to the ground in the mobile home (and therefore back to the service). A phone line in the wellhouse would be a metallic path. So would metal water pipe to the mobile home.
* there is no ground fault protection on the supply side of the feeders.
NEC 250.32 (B) (2)
In any case (either with 3-wire or 4-wire feeders), a ground rod(s) (and other bonding) is required at the wellhouse.
Jim x 3
Edited 8/30/2009 2:47 pm ET by jimjimjim
Two problems with that.One a 3 wire feed to outbuildings is not allowed in the 2008 NEC (and earlier is some locations) and it appears that he is covered by the 2008.And 2nd't he said that the feed is 2 hots and a ground. Can't made a ground into a neutral..
William the Geezer, the sequel to Billy the Kid - Shoe
Bill,
Yep, thanks, a bare or green ground (if that's what 08 has) can't be used as a neutral.
The code does change, so relevant code is a consideration. The 2008 code still has the exception, but with tighter language.
Regards,
Jim x 3
the ground wire was not marked, although we marked it with green tape in the new installation. By the way, the current owner is not the original owner/installer. She purchased this can of worms, and is doing her best to make it safe.
Bill, the service entrance where the well wires originate, is a grounded neutral, so the neutral and grounds are on the same bar. This is an existing condition, as I see it, pretty much the same as a 50A range circuit. Currently requires a 4 wire circuit, but an existing 3 wire doesn't need to be removed or replaced, correct? Isn't the existing, buried wire covered by the code under which it was installed 25 years ago?
Yes, the feeder would be grandfathered IF it has 2 hots and NEUTRAL.What kind of cable is this. If it is USE with a bare wrapped around the two hots and covered with a sheath then that is a neutral. And the two hots are black and or black and red.However, if it is something like UF then you have a black and white and a ground wire. And that is fine for a 240 only branch circuit, but you can't get 120 from it..
William the Geezer, the sequel to Billy the Kid - Shoe
Bill, The feed was individual USE conductors, with the smaller (one gauge smaller) of the 3 being used as the ground. It was not color coded, so I marked it with green tape. It could be as easily marked with white. The owner is making a polite request to the inpsector, citing NEC 250.32(B)(2), which I have also read, and seems to apply. I confirmed for her the lack of metallic return paths, visually. I am reasonably sure this is what is being done on these installations, because, as I mentioned previously, these service entrances are failing regularly, and being replaced without 4 wires to the pump houses. Thanks for all the information.
The exception you cite pretty much went away with the 2008 edition of the NEC. One service drop, one cervice, and all else is a 'sub' panel. Since it's new work, the new rules apply.
Now, HAD the original guy taken my advice, and run the wires in pipe, adding that fourth wire might not be a problem.
Reno et al:
I think we could make a case that the wiring to and in the wellhouse is existing premise wiring. Here, all of that would have been out of the scope of the service change inspection. But of course the inspector there has the most important opinion about that.
I'm surprised that Junkhound didn't implement his 120V loads on a 2:1 autotransformer.
I agree completely that a 4-wire solution with separate neutral and ground is best.
Regards,
Jim x 3
Edited 8/30/2009 7:36 pm ET by jimjimjim
Existing or not, it was done wrone, to unrealistic expectations, the first time. There's no good reason to put a patch on a bandage on a jury-rig to cobble it into something that kida, sorta 'works.'
Code language was, up to the 2008 edition, poor, and was understood by some to allow - in some circumstances - a separate building to be treated as a separate service. Aplying that idea to an outbuilding was never the intent, but code authorities can only enforce what's written - not what was meant.
In this very forum, time and again we have some poster saying something like "but I only want to power a pump" or "I just want to add a welder." I'm sorry, but there's no substitute for good design. You can pay a little more now for a good design - or you can pay a lot later to re-do everyting, complete, when you outgrow your 'code minimum' effort.
That's why the NEC starts out by plainly stating that it is not a design manual. We get in these messes when folks try to 'finesse' the code .... and I have no sympathy when they later come crying that their efforts were inadequate.
The OP ran out of legitimate options a long time ago; now it's time to rip it all out and start over.
Junkhound didn't implement his 120V loads on a 2:1 autotransformer
Simple, either you have the inconvienience of needing to switch the xfmr or you eat the cost of core losses 24/7. <G>
The pre exising condition is how others in this situation, locally have dealt with it, as have most inspectors. She apparently drew the short straw in the inspector department, as I have found this particular inspector has a reputation such, that some contractors won't be on site when he is scheduled. He has the reputation of "do it this way, because I said so". I've never met him, and my experiences with inspectors over 25+ years has been 95% positive. But, unfortunately you tend to remember the ones that have an attitude.
I, for one, always run underground in pipe,never a direct burial. Heard all the horror stories
This is exactly what I needed. And her property meets all those conditions. As I mentioned in a previous post, these installations are being upgraded regularly around here without a new line to the well house. Thank you very much.