SER in PVC & Heat

Status
Not open for further replies.
J

johnjustjohn

Member
Location
New York
I've asked this question of several licensed electricians and none of them agree on an answer. To upgrade the service on my house the panelboard will be located about 30 feet from where the service entry cable enters a crawl space. I understand that I'll need an outside disconnect, SEU outside and SER inside. All agree. 2/0 copper will be used as is standard here on Long Island. Two of the electricians I've spoken to say that for the inside run, conduit isn't necessary. One says it's a good idea.

I've decided that since I'm the one crawling around under the house working on things that I'd like the SER inside a conduit, say PVC Schedule 80. My question is this: Do I need to consider heat build up inside the conduit? Can I just ask my electrician to put the 2/0 SER inside 2' PVC? What section of the NEC talks about this?

I like to know as much as possible about a job, especially when I need to hire someone to do it.

Thanks,

John
 
G

gregory

Senior Member
Re: SER in PVC & Heat

John,
Schedule 80 would be a good choice for the feeder. In a crawl space it could be subject to mechanical injury. They should be protected in schedule 80 to a height from grade to 8 feet. PVC should be strapped every 4 1/2 feet.

Heat build up would not be a factor because you have only 2 current carrying conductors in the conduit. Consideration should be given if you are running the conduit in a hot area. such as an attic or furnace room or in direct sunlight.

Do not forget that you must run the service grounding electrode conductor to the outside disconnect, not the sub panel that you are installing in the home. You will need a equipment grounding conductor from the outside disconnect to the inside panel. The equipment grounding conuctor must be installed in the pvc. do not bond or ground the inside neutral at the sub-panel.

Greg
 
C

curt swartz

Electrical Contractor - San Jose, CA
Location
San Jose, CA
Occupation
Electrical Contractor
Re: SER in PVC & Heat

If your going to be installing a PVC raceway between the exterior disconnect and the interior sub panel there is no reason to use SER cable. Your electrician should just use 4 individual conductors.
 
B

BAHTAH

Senior Member
Location
United States
Re: SER in PVC & Heat

If you plan on installing conduit from the service disconnect to a sub panel, why not use 2/0 THWN-CU and EGC instead of trying to pull the SER cable in the conduit? PVC Sch-80 should be sunlight resistant and meet the requirements for use where subject to physical dammage if installed on the exterior of your home.
 
iwire

iwire

Moderator
Staff member
Location
Massachusetts
Re: SER in PVC & Heat

As far as the NEC, there is no requirement to run this in pipe, not that it is a bad idea, and you may have local ordinances that go beyond the NEC.

As has been said if you go with pipe, run separate conductors, it can be difficult to put SER in pipe.

The NEC does have rules about heat build up they take effect when there is more than 3 "current carrying" conductors in a raceway or cable, this will not effect you, in you case the grounding conductor and the grounded conductor (the neutral) are not considered current carrying conductors.
NEC 310.15(B)(2)(a)(4) and (5)

Remember that once the service entrance conductors (the SEU) go into the "Service Disconnect" (the disconnect outside) they end, and the wires leaving it are now "Feeders" and follow the same rules that any feeder would have, which are more relaxed rules then for "Service Entrance Conductors"
Look in article 100 for the definitions of "Service Entrance Conductors" and "Feeders"

To see some pictures of SER used as feeders and some discussion on it click on the link.

SE Used as Feeders

[ March 19, 2003, 05:53 AM: Message edited by: iwire ]
 
Status
Not open for further replies.
Top