Service Drop wire size from weatherhead

Reply

  #1  
Old 03-26-10, 09:48 AM
Member
Thread Starter
Join Date: Mar 2010
Location: USA
Posts: 6
Received 0 Votes on 0 Posts
Service Drop wire size from weatherhead

I did a search but did not see this answered anywhere.

I am in the process of preparing to replace my main panel and sub panel with a new single panel 40 position unit. I was originally only planning on installing 125 amp service to alleviate having to replace the service wire from the pole.

After calling the local utility and having them come out and look at my overhead lines, they have rated the 1/0 triplex wire to 200amps (how, I do not know). Since discovering this, I am just going to go ahead an and install a 200 amp, 40 position panel as they can be had for ~$125

In doing this, I will need to install a new conduit from the panel, new meter base and new weather head. My question is what size wire should I be running from the existing overhead lines to the meter? And from the meter to the 200 amp main. I did not think the 1/0 would be big enough.

I will not personally be disconnecting or reconnecting to the mains.

Thanks.
 
Sponsored Links
  #2  
Old 03-26-10, 10:06 AM
pcboss's Avatar
Forum Topic Moderator
Join Date: Jul 2002
Location: Maryland
Posts: 14,983
Received 35 Votes on 30 Posts
The correct sizes would be 4/0 AL or 2/0 copper. These will need to be marked "Sunlight Resistant".
 
  #3  
Old 03-26-10, 10:35 AM
Member
Join Date: Feb 2010
Location: United States
Posts: 461
Received 0 Votes on 0 Posts
Originally Posted by 68droptop View Post
I did a search but did not see this answered anywhere.

I am in the process of preparing to replace my main panel and sub panel with a new single panel 40 position unit. I was originally only planning on installing 125 amp service to alleviate having to replace the service wire from the pole.

After calling the local utility and having them come out and look at my overhead lines, they have rated the 1/0 triplex wire to 200amps (how, I do not know). Since discovering this, I am just going to go ahead an and install a 200 amp, 40 position panel as they can be had for ~$125

In doing this, I will need to install a new conduit from the panel, new meter base and new weather head. My question is what size wire should I be running from the existing overhead lines to the meter? And from the meter to the 200 amp main. I did not think the 1/0 would be big enough.

I will not personally be disconnecting or reconnecting to the mains.

Thanks.
The PoCo has there own rules governing the wire size from the pole to the house. Most house that get upgraded to 200 amp services never have there service drops changed. Most houses still and will always have orginal service drops.
 
  #4  
Old 03-26-10, 10:35 AM
Forum Topic Moderator
Join Date: Feb 2005
Location: Near Lansing, Michigan
Posts: 10,944
Received 42 Votes on 40 Posts
Originally Posted by 68droptop View Post
they have rated the 1/0 triplex wire to 200amps (how, I do not know).
Wires hanging in free air are naturally convection cooled allowing them to safely carry significantly more current than their conduit-enclosed counterparts.

My question is what size wire should I be running from the existing overhead lines to the meter?
#2/0 copper or #4/0 aluminum. THWN-2 with UV resistance or XHHW are common types of wire you can use for this.
 
  #5  
Old 03-26-10, 06:47 PM
Member
Thread Starter
Join Date: Mar 2010
Location: USA
Posts: 6
Received 0 Votes on 0 Posts
Thanks for the responses. I think I will go copper so I can use a smaller conduit.
 
  #6  
Old 03-27-10, 01:00 AM
Member
Join Date: Mar 2006
Location: NE Wis / Paris France{ In France for now }
Posts: 4,808
Received 0 Votes on 0 Posts
You will need 2 inch conduit for this one due the conductor size I know you say 70mm˛ { 2/0 AWG } copper and the other gotcha is if you going with telescope mode { go thru above the roof line } majorty of POCO { power company } will required 2 inch ridge steel conduit and may have to back guyed due some span will need to support the POCO conductors.

Merci,Marc
 
  #7  
Old 03-27-10, 07:59 AM
Forum Topic Moderator
Join Date: Feb 2005
Location: Near Lansing, Michigan
Posts: 10,944
Received 42 Votes on 40 Posts
Originally Posted by 68droptop View Post
I think I will go copper so I can use a smaller conduit.
You could put (3) #2/0 in a 1-1/2" conduit, but you will have a better day if you use 2", especially if there are any LB fittings.
 
  #8  
Old 03-27-10, 08:07 AM
CasualJoe's Avatar
Member
Join Date: Jan 2010
Location: USA
Posts: 10,239
Received 40 Votes on 32 Posts
Some overhead meter sockets come with a 2" hub factory installed on top of the socket. I have always considered 2" conduit a standard on a 200 amp service.
 
  #9  
Old 03-27-10, 05:55 PM
Member
Join Date: Feb 2010
Location: United States
Posts: 461
Received 0 Votes on 0 Posts
Originally Posted by CasualJoe View Post
Some overhead meter sockets come with a 2" hub factory installed on top of the socket. I have always considered 2" conduit a standard on a 200 amp service.
Most if not all 200 amp meter pans come with the hub as well.
 
  #10  
Old 03-27-10, 06:27 PM
badeyeben's Avatar
Member
Join Date: Dec 2006
Location: Southern ILLINOIS
Posts: 952
Received 0 Votes on 0 Posts
Every power company I have worked with will supply a spec sheet that details what size wire you need. Also grounding details and ground rod details such as how deep it needs to be below ground and how far away from the footings. Also will specify what size conduit and how many clamps it needs and how far apart the clamps go. Remember the power company has the last say on if they connect to your setup or not.
 
  #11  
Old 03-27-10, 06:43 PM
Member
Join Date: Feb 2010
Location: United States
Posts: 461
Received 0 Votes on 0 Posts
Originally Posted by badeyeben View Post
Every power company I have worked with will supply a spec sheet that details what size wire you need. Also grounding details and ground rod details such as how deep it needs to be below ground and how far away from the footings. Also will specify what size conduit and how many clamps it needs and how far apart the clamps go. Remember the power company has the last say on if they connect to your setup or not.
Thats not entirely true. At least in NJ its not. In order for a cut in card to be issued for a service connection, it needs to be locally inspected first. NEC regulates grounding and wire sizes etc... If it is not up to code then it wont pass local inspection and it will never even get to the power company for approval. Usually, and i mean 100 % of the time, if it passes local inspection, it passes PoCo inspection.
 
  #12  
Old 03-27-10, 07:57 PM
CasualJoe's Avatar
Member
Join Date: Jan 2010
Location: USA
Posts: 10,239
Received 40 Votes on 32 Posts
I have also seen a lot of those spec sheets from the power companies and have found they always conform the NEC and local amendments except that the power company has the right to specify the meter socket to be used, location of the service and sometimes the diameter of the rigid steel conduit mast in reference to the height above the roof. It's hard to imagine, but I have seen quite a few 2" rigid steel conduit masts that had been bent by the pull of the service drop.
 
  #13  
Old 03-27-10, 09:18 PM
Member
Join Date: Mar 2006
Location: NE Wis / Paris France{ In France for now }
Posts: 4,808
Received 0 Votes on 0 Posts
Originally Posted by CasualJoe View Post
It's hard to imagine, but I have seen quite a few 2" rigid steel conduit masts that had been bent by the pull of the service drop.

CJ.,

Ya are not alone on this one I have see it even with big 4 inch ridge conduit for riser it do bent from weight of ice plus few trucks snag it.

In my area in Wisconsin the 2 inch ridge is the smallest they will allow for perescope { thru the roof } set up on single phase but for three phase service it will be minuim of 3 inches ridge.

And all prescope must have backguyed attached to the structure member not the roof sheeting alone.

In France it automatic backguyed with ridge conduits regaurdless of size.

Merci,Marc
 
  #14  
Old 03-30-10, 10:24 PM
Member
Thread Starter
Join Date: Mar 2010
Location: USA
Posts: 6
Received 0 Votes on 0 Posts
A couple of things. The power company was quite specific that the do not recommend and power drop requirements for residential installations. It is completely up to the local requirements. My city inspector only said it must conform to NEC specs.

As for the mast, it will be attached to the rear of a 2 story home and the overhead wire will be attached to a tie off insulator bolted into the second story rim joist. There will be no weight on the mast itself.

Thanks again.

Oh and I stopped in to the local Home Depot for a couple of other items and the person in the electrical department (said he was a retired electrician, but you never know) said that I could use THHN for the wire. I thought I needed to use sunlight resistant and THHN isn't, is it?
 
  #15  
Old 03-31-10, 09:11 AM
Forum Topic Moderator
Join Date: Feb 2005
Location: Near Lansing, Michigan
Posts: 10,944
Received 42 Votes on 40 Posts
Originally Posted by 68droptop View Post
As for the mast, it will be attached to the rear of a 2 story home and the overhead wire will be attached to a tie off insulator bolted into the second story rim joist. There will be no weight on the mast itself.
In that case, the mast can be regular PVC conduit. It should be supported with a pipe hanger or strap every 3' up the side of the house.

I thought I needed to use sunlight resistant and THHN isn't, is it?
Some is, some isn't. It's usually printed on the wire if it's sunlight resistant. You also could consult the manufacturer's spec sheet which are often online. Here's Cerrowire brand:

THHN/THWN-2

They state that their black THHN/THWN-2 is sunlight resistant. The surface print on the wire also includes "SUNLIGHT RESISTANT" according to the spec.
 
Reply

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Thread Tools
Search this Thread
 
Ask a Question
Question Title:
Description:
Your question will be posted in: