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#196093 09/13/10 12:47 PM
Joined: Oct 2009
Posts: 10
evad73 Offline OP
Member
Where in the code do you find size of service mast rigid pipe thru a roof? Does it need to be 2 inch?

Joined: Jul 2004
Posts: 9,923
Likes: 32
G
Member
238.28 just says "... it shall be of adequate strength or be supported by braces or guys to withstand safely the strain imposed by the service drop."

This is not a design manual wink

You probably have a local interpretation that makes that 2" or larger. but the NEC only defines the size in the sense that it has to be able to contain the service entrance conductors (raceway fill).


Greg Fretwell
Joined: Aug 2006
Posts: 356
Member
The requirement is from your local power company.
This part of CA, PG&E requires a minimum of 1.25" IMC or RMC for overhead service if the service will be attached to the mast. The size will also depends on conduit fill.


Be kind to your neighbor, he knows where you live

Joined: Jan 2005
Posts: 5,445
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Cat Servant
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The actual specifics of a service drop are found in your Power Company's standards. Most PoCo's have these specifications availble, free, over the internet.

2" rigid or IMC is a common requirement. Also pay close attention to the additional bracing requirements if the mast extends more than 30" above the roof.

Joined: Oct 2009
Posts: 10
evad73 Offline OP
Member
Thanks, Xcel Energy "Service masts shall be 2" minimum GRC metallic conduit."

Joined: Jul 2004
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G
Member
It is the PoCo that ultimately decides if this is a service mast or a flag pole* so you have to go by what they say.

(*as in, if they won't hook up power it is a flagpole) wink


Greg Fretwell
Joined: Sep 2002
Posts: 943
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N
Member
Originally Posted by Niko
The requirement is from your local power company.
This part of CA, PG&E requires a minimum of 1.25" IMC or RMC for overhead service if the service will be attached to the mast. The size will also depends on conduit fill.


I learned the hard way that SMUD's (Sacramento Muni. Utility District) has a 1 1/2" min size, found out before it was installed but was a pain....

Joined: Jul 2004
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G
Member
These days the PoCos usually have their service design specifications online so it is worth downloading that and printing it out.

FPL is here

http://www.fpl.com/doingbusiness/builder/contents/ESS_toc.shtml


Greg Fretwell
Joined: Oct 2000
Posts: 4,116
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Minimum 2-1/2" Rigid here on Long Island (NY) if it supports the service drop.

Some local Utility requirements:

http://www.lipower.org/pdfs/commercial/redbook/Chapter11.pdf

Bill

Last edited by Bill Addiss; 09/14/10 02:14 AM. Reason: added link
Joined: Jun 2006
Posts: 613
M
Member
In Canada About 2 codes ago the 2 inch rigid pipe as a mast was replaced by an approved mast which when field measured turns out to be more like a schedule 80 2 1/2" rigid steel pipe without the threaded ends and available in 10 and 12 foot lengths. Although rare some 2" pipes were getting bent.
There is a set screw adaptor to convert from the mast to a 2" threaded hub on top of the meter base.


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