Return to the Electrical Wiring Forum | Post a Follow-Up

 o
service entrance 100amp to 200 code questions

Posted by nogreenthumbs (My Page) on
Wed, Apr 24, 13 at 18:33

Hello all,

I recently pulled a permit to have my overhead electrical lines buried(underground service). Currently our home is 100 amp service and the POCO will be putting in 200 amp service feeders underground. POCO is doing all work UP TO meter can and I am doing the rest. Current house set-up is 100 amp service from meter can to 100 amp disconnect, from disconnect to 100 amp main panel about 25' away. There are also no ground rods on this house. Home is grounded from main panel to water pipe.

I am wanting to just leave all the 100 amp stuff just the way it is. I am not ready at this time to switch the panel and everything over to 200 amp. That means that I would have feeders only rated at 100 amps (#2AL) coming out of the 200 amp meter can going to my 100 amp disconnect. Is this allowed?

Also, on the ground rods. I know I need two ground rods 8' long and 6' apart. What I'm not sure is does the ground conductor go to the disconnect and then the main panel becomes a sub-panel, or does the ground conductor go right to the main panel? I've talked to a few electricians/searched the web and everyone has a different answer.

Thanks for any info,
Ron


Follow-Up Postings:

 o
RE: service entrance 100amp to 200 code questions

I've just had this done last fall and kept everything at 100 amps after the meter. The meter is now rated at 200 amps. Disconnect right after the meter is the main panel and everything else is now a sub-panel. Electricians seperated all the neutrals and grounds in the original main panel and the inspector did pull the cover to check.


 o
RE: service entrance 100amp to 200 code questions

Installing a 200 amp meter socket at this time would be one of the smartest things you could do. No problem with having 100 amp conductors on the load side of the meter.


 o
RE: service entrance 100amp to 200 code questions

Ok bus_driver thats good to know. I will have 100 amp conductors on the load side of meter going to disconnect, then to main panel. Do you know if I have to isolate all neutrals/grounds in panel? I've had journeyman electricians I know at work say two different things to me.(They freely admit they don't know for sure about residential code) One says the main panel is actually a sub panel becuase of the disconnect, others say the opposite. This also has me confused on how to do the ground rod conductor. Does ground conductor go to disconnect(there is no place for it but I know I can buy a lug for it)then to main panel or just to the main panel?

Thanks for all your help,
Ron


 o
RE: service entrance 100amp to 200 code questions

The disconnect serves as the point of service- the grounded service conductor connects to the grounding electrode conductor here.

The grounded electrode conductor connects to the ground rods. It's better to increase the spacing to twice the length of the rods; 8' x 2= 16' spacing, instead of 6'.

The panel needs to have the neutrals isolated from the ground bar.

This post was edited by mm11 on Fri, Apr 26, 13 at 10:52


 o
RE: service entrance 100amp to 200 code questions

Yes, as shown by the picture, if the main panel is not itself serving as the service disconnect (which in many cases is the cheapest and easiest way to go), then you must keep the grounds and neutrals separate there (and every where else downstream).

Caught my guys napping one day doing my whole house generator. My main panel is not the service disconnect which is between the meter and he automatic transfer switch. Fortunately for them, it was just a matter of wrestling another conductor through a short section of conduit.


 o
RE: service entrance 100amp to 200 code questions

Think I got it. Please let me know if this is right.

Grounding electrode conductor starts at ground rod 1, goes to ground rod 2, into house and connects to 100 amp disconnect load side neutral, then on to water pipe, all unbroken.

The breaker panel then becomes a sub-panel. Where do I connect the ground(bare)wire from breaker panel to the disconnect?

Thanks,
Ron


 o
RE: service entrance 100amp to 200 code questions

The ground rods need to be driven at the point of service- the disconnect. The grounding electrode conductor starts at the furthest ground rod, goes to second, and terminates in the disconnect.

" Where do I connect the ground(bare)wire from breaker panel to the disconnect? "

Look at the pic above. The panel neutral goes to the disconnect, and terminated on the neutral bar, which is bonded to ground at the service.

Make sure the bare neutral conductor does not touch the panel. If that occurred, the neutral would be bonded again, which is not acceptable. It would be better to have an insulated neutral- SER instead of SEU.


 o
RE: service entrance 100amp to 200 code questions

There's NO SUCH THING as a bare neutral on the house side of the service disconnect. If you've got a bare neutral, you've done it wrong.


 o
RE: service entrance 100amp to 200 code questions

I'm guessing nogreenthumbs has SEU jumping from the disconnect to the panel, from his description of the installation.

OP- Is my hunch correct? SEU cable, not SER?


 o
RE: service entrance 100amp to 200 code questions

That was my guess as well, but it's still not legal.
The bare GROUND in the SE cable is fine for use as the ground. It can not be the neutral.

There's an exception for certain EXISTING installations but none of that applies here (even if it weren't new work).


 o
RE: service entrance 100amp to 200 code questions

The cable is SER. 2-2-2-4. The disconnect I have(cutler hammer) is proving to be more difficult for me than a panel would be. I'm not sure what to do. There is no room in the disconnect to terminate the ground electrode conductor or the bare wire from breaker panel. I'm not sure if they make a bar I could mount in there. Maybe you can see from the pic. Also note the cable coming in on left is still my OLD CABLE to the breaker panel. I have the new 2/2/2/4 cable all ready to go I just have to figure out what to do. I think I may just go buy a 100 amp panel and put in a 100 amp breaker for the breaker panel for the house. Open to suggestions.

Thanks,
Ron


 o
RE: service entrance 100amp to 200 code questions

Another question that wasn't answered in its entirety, or I just didn't get it. Where does the ground electrode conductor from water pipe go? I was under impression the path of ground electrode conductor was from ground rods, to service disconnect, to water pipe, all unbroken.

Ron

This post was edited by nogreenthumbs on Sun, Apr 28, 13 at 13:31


 o
RE: service entrance 100amp to 200 code questions

If anyone is interested I found out what I need to do. Dad came through by talking with a distant neighbor of his who is a supervisor/residential electrician.

Gound electrode conductor goes from ground rods to service disconnect and terminates there(I have to buy a ground bar/lug for this). The bare/ground from my 2-2-2-4 cable also terminates on same ground lug in service disconnect. In breaker panel I need to remove bonding screw and isolate all grounds to their own bar(s) and neutrals to their own bars. Bare wire from 2-2-2-4 cable and water pipe ground wire also go to ground bar in breaker panel.

The disconnect is what had me all confused. Not having ever wired one I wasn't sure what to do as far as code goes. One thing the neighbor said I have to do in the service disconnect when I put in the ground bar/lug is that it either needs to be drilled and tapped or nut/bolted. He said absolutely NO to using a self-tapping screw.

Thanks again for all your help,
Ron


 o
RE: service entrance 100amp to 200 code questions

First off, that's a particularly unprofessional installation. The feeder neutral should NOT block access to the fuses.
The rest is pretty sloppy and screams that it was done by an amateur.

Your neighbor is giving you good advice. You can not use a self tapping screw. Further, if it is serving as part of your main bonding, there are specific requirements as to sizing. You would be better off using specifically listed accessories for your disconnect rather than just poking at it at random.

As you've been told COUNTLESS times. The ONLY place the grounds and the grounded conductor (NEUTRAL) are allowed to come together is in the disconnect. You must isolate it EVERYWHERE else. Yes this means isolating the ground and neutral buses (which depending on the panel may require you to install an additional grounding bar) and making sure all the wires land on the right bar.

There are TWO types of water piping ground that you have to worry about. The first is the metal piping that comes in from at least 10' of earth contact. This is part of your grounding electrode system. It needs to run directly to your disconnect (perhaps connected to the other electrode conductors via approved fasteners. Note that these connection requirements are different than for other conductors.

The SECOND thing is the metal piping that may exist inside your house. This must be BONDED. Now the fact it SHOULD be already connected as a grounding electrode would suffice except you need to assure that things like water meters, hot water heaters, etc... do not interrupt the continuity (you may need to bond across these units).


 o
RE: service entrance 100amp to 200 code questions

Thank you ronnatalie for your advice. Understand I AM an AMATEUR. Otherwise I wouldn't be on these boards. Also, if you read one of my previous posts you would know that the reason that cable is terminated like that is because its only temporary. I have the right wire all ready to go I just didn't have the time and had to get the power back on in the house. As for the rest of it being sloppy, well I disagree. The only part left is the line side at top and I think it is terminated just fine. What would you have done different?

And yes I have been told countless times. The problem is everyone has a different answer, which makes me leary. Two things in particular are the neutrals/grounds in the service disconnect and the water pipe(the 10' from earth contact one). The neighbor said NOT to bond the neutrals/grounds in the service disconnect. He also said the water pipe ground can go to the sub-panel. I myself thought the water pipe ground had to go back to the service disconnect.

So you see, it can be confusing for an amateur. I AM trying to do the job right, and most importantly safe.

I truly do appreciate yours and everyones feedback.

Thanks,
Ron


 o
RE: service entrance 100amp to 200 code questions

Well he is WRONG. The neutral must be connected to the ground in the service disconnect.

The WATER pipe where it comes in from the underground outside (if it is metal) *MUST* be connected with the other grounding electrode system (ground rods) i.e., back to the service disconnect. If it were just an issue of being a BOND for the house piping, you could connect it to some other convenient grounding point, but that is NOT the case on the incoming water service (if metal and underground).

While the disconnect didn't need fuses, If you're going to have them there, you should leave them accessible, even if that rats nest is only temporary.


 o Post a Follow-Up

Please Note: Only registered members are able to post messages to this forum.

    If you are a member, please log in.

    If you aren't yet a member, join now!


Return to the Electrical Wiring Forum

Information about Posting

  • You must be logged in to post a message. Once you are logged in, a posting window will appear at the bottom of the messages. If you are not a member, please register for an account.
  • Posting is a two-step process. Once you have composed your message, you will be taken to the preview page. You will then have a chance to review your post, make changes and upload photos.
  • After posting your message, you may need to refresh the forum page in order to see it.
  • Before posting copyrighted material, please read about Copyright and Fair Use.
  • We have a strict no-advertising policy!
  • If you would like to practice posting or uploading photos, please visit our Test forum.
  • If you need assistance, please Contact Us and we will be happy to help.


Learn more about in-text links on this page here