View Full Version : How to run 4 wire from disconnect to electrical panel
stoner86
Jul 30, 2010, 02:29 PM
I am installing a new 100 amp panel. Where the se cable enters house if further then 3 ft. I am going to use a 100 amp disconnect then run wire from disconnect to panel. My inspector says I must run 3 wire to disconnect then use 4 wire from disconnect to the panel and isolate the neutral bar and ground the appliance bar. Not sure what he means by this also do I run my ground wire to the water main and ground rods from the panel or the disconnect? I have installed panels before but never with a disconnect, any help would be greatly appreciated. Thanks
donf
Jul 30, 2010, 03:23 PM
Help, please.
Why are you installing a new 100 amp panel? Is this a service panel or a sub panel?
What do you mean by, "if further than 3 ft."? Three feet from what to to what?
Do you already have a main service panel?
From the information you are giving us I strongly suggest you go back and talk to the inspector.
KISS
Jul 30, 2010, 03:28 PM
When wiring, Pretend that the disconnect is the main panel.
So what do you do. The ground rod(s) as well as the neutral ground bond occurs there. You may need two ground rods depending on code.
If the disconnect is fused the panel can be main lug or main breaker. If not, then it must be a main breaker type of panel.
The new panel will have the ground/neutral bonding screw removed and you will usually have to purchase a ground bar kit, so you can keep the grounds and neutrals separate.
Which means, 3 wire to the disconnect (+ ground rods and bonding) and 4 wire to the panel.
Someone else has to clarify whether the plumbing bond can be made at the panel. I suspect the bond may or not be able to be made there to be depending if it's used as the grounding electrode.
donf
Jul 30, 2010, 03:44 PM
Kiss,
We have to know whether this is a main service panel or a sub panel prior to advising the poster on the grounding of the panel.
The use of one or more grounds is dependent on the resistance of the soil, not the code. If the resistance between the ground rod and the soil is greater than 25 Ohms, then a second ground rod must be bonded to the first from a distance no closer than 6'.
We need to know what the panel is to be used for before we can actually answer this question.
KISS
Jul 30, 2010, 04:19 PM
This:
I am installing a new 100 amp panel. where the se cable enters house if further then 3 ft. I am going to use a 100 amp disconnect then run wire from disconnect to panel.
Answers the question. New main panel in a new location with an outdoor disconnect because it's greater than 3' away.
Remember the stuff about supplimental and main grounding electrode? It's difficult to know the resistance of the soil without driving another rod.
stoner86
Jul 30, 2010, 05:00 PM
The customer has the old screw in fusebox for her panel and would like it replaced with a new breaker box so it is the main panel. Where the se cable enters her basement I will have to run roughly 25 ft to the panel this is why I am installing a disconnect switch, sorry for the confusion
KISS
Jul 30, 2010, 06:01 PM
Article 250.104 (2008 NEC) a says the plumbing should be boded to service equipment enclosure, the grounded conductor at the service.
So, this suggests the disconnect.
Missouri Bound
Jul 30, 2010, 06:03 PM
Stoner... KISS has you on track, follow his advice and you will be fine.
stanfortyman
Jul 30, 2010, 06:03 PM
the customer has the old screw in fusebox for her panel and would like it replaced with a new breaker box so it is the main panel. Where the se cable enters her basement i will have to run roughly 25 ft to the panel this is why I am installing a disconnect switch, sorry for the confusion
Customer?
You are doing this job for a customer, for pay, and you don't know what you are doing? You need the inspector and an internet DIY forum to explain your job to you?
Sorry, but this bothers me. :mad:
My inspector says i must run 3 wire to disconnect then use 4 wire from disconnect to the panel and isolate the neutral bar and ground the appliance bar. Not sure what he means by this...Wow.
stoner86
Jul 30, 2010, 07:48 PM
Sorry stanfortyman I thought this site was Askmehelpdesk not what your feelings and opinions are. I don't see how my question is any different from the others on this site. I couldn't care less what you think, its rude ****** like you that bother me! Oh and fyi I never said anything about pay, and the "customer" is an elderly women that lives near me. Thanks Kiss your answers really helped, I appreciate it
stanfortyman
Jul 31, 2010, 05:56 AM
Stoner, if you don't want opinions I suggest you keep off all internet forums. You are going to get them whether you want them or not.
Second, you though I was a rude *profanity edited*? Seriously?
Man, you need to toughen up a little bit. I was FAR from rude.
Besides, you say you couldn't care less what I think, yet I bother you. Hmmmm. Freud would have fun with you. :D
Lastly, you say this is for a customer (http://wordnetweb.princeton.edu/perl/webwn?s=customer), but we should not assume you are being paid? Give me a break. :rolleyes:
Sorry if my professional opinion bothers you so much. It's just professionals like me lose a lot of work to trunk slammers & handymen like you.
donf
Jul 31, 2010, 06:28 AM
Stoner,
The fact that you did not understand the inspector makes sense now.
Regardless of whether you will get paid (I do work for free for the elderly all the time). But I also study what I'm going to be doing.
Swapping out a main service panel is routine work but you could still get dead or seriously burned if you screw up.
Is the new panel going to be in the same place as the old panel? If it is not, then you need to talk to the power company to make sure that they agree to the move.
The NEC allows for only one service entrance point in a residential unit and that entry point is required to be as close to their equipment as possible. 25' is not as close as possible.
Also, here are rules that govern the running of service cable a greater distance.
Requiring a service disconnect on the outside of a residence is pretty much a standard practice. It's a safety rule and the NEC is a safety manual.