Go Back   DIY Chatroom Home Improvement Forum > Home Improvement > Electrical

CLICK HERE AND JOIN OUR COMMUNITY TODAY...IT'S FREE!

Reply
 
Thread Tools Search this Thread Display Modes
Old 05-26-2011, 11:30 AM   #1
I ask the impossible!
 
Join Date: Aug 2010
Location: Royal Oak, Michigan
Posts: 1,061
Blog Entries: 7
Share |
Default

Service mast bracing


One of my corrections my inspector required was bracing the service mast because he goes by the height of the weatherhead. So I intend to brace it using 3/4" EMT conduit with the ends flattenned and drilled so it can be bolted at the insulator clamp at the top and bolted to the roof at the bottom.

My question is if there would be any issue doing the bottom attachment using lag screws into rafters, or if I should use carriage bolts with plates on both sides?

My plan for bracing is based on this:
http://www.electriciantalk.com/f9/he...er-mast-10341/

__________________
Please do NOT consider any "before" picture of my house as any kind of endorsement of any particular construction method. In fact, you should probably assume that if I post a "before" picture, I am posting it because I am soliciting advice on a proper replacement for one of MANY things done wrong by a previous owner.
WillK is offline   Reply With Quote
Old 05-26-2011, 02:26 PM   #2
Electrical Contractor
 
Join Date: Feb 2008
Location: Colonia, NJ
Posts: 127
Default

Service mast bracing


Use a guy wire system. Available at the electrical supply house.

hpp58 is offline   Reply With Quote
Old 05-26-2011, 02:31 PM   #3
I ask the impossible!
 
Join Date: Aug 2010
Location: Royal Oak, Michigan
Posts: 1,061
Blog Entries: 7
Default

Service mast bracing


Yeah... inspector didn't like the guy wire idea.

I wish I had a chance to take a picture of another service entrance in the neighborhood. It's SEU cable. It goes up and forms the drip loop. It's suspended in the air and at the top it's about a foot from the house. It's not secured AT ALL to the wall. It's a corner house on the next street over from me.
__________________
Please do NOT consider any "before" picture of my house as any kind of endorsement of any particular construction method. In fact, you should probably assume that if I post a "before" picture, I am posting it because I am soliciting advice on a proper replacement for one of MANY things done wrong by a previous owner.
WillK is offline   Reply With Quote
Old 05-26-2011, 05:38 PM   #4
Scared Electrician
 
Saturday Cowboy's Avatar
 
Join Date: Nov 2009
Location: Colorado
Posts: 715
Default

Service mast bracing


why won't he let you use a guy wire??? It is better and does less damage to the roof.
__________________
Ragged Trousered Philanthropist


Please follow the code - its there for your safety no matter how inconvenient.
Saturday Cowboy is offline   Reply With Quote
Old 05-26-2011, 05:48 PM   #5
I ask the impossible!
 
Join Date: Aug 2010
Location: Royal Oak, Michigan
Posts: 1,061
Blog Entries: 7
Default

Service mast bracing


He doesn't like the idea of it breaking and whipping around and hitting the hot conductors, plus he says he'd require one that has a UL listing for the application which he doesn't think there is such a thing.

Personally I'm all for 3/4" tube. I'd be able to do the strength calculations myself if I had to.

I really haven't been able to find any sort of guy wire system in my online searching, aside from some Thomas and Betts stuff that was only available in Canada. I saw some things for antenna applications, and some of the discussions I came across elsewhere made it sound like there's a move away from guy wire support for service masts.
__________________
Please do NOT consider any "before" picture of my house as any kind of endorsement of any particular construction method. In fact, you should probably assume that if I post a "before" picture, I am posting it because I am soliciting advice on a proper replacement for one of MANY things done wrong by a previous owner.
WillK is offline   Reply With Quote
Old 05-26-2011, 06:11 PM   #6
Scared Electrician
 
Saturday Cowboy's Avatar
 
Join Date: Nov 2009
Location: Colorado
Posts: 715
Default

Service mast bracing


ok....
__________________
Ragged Trousered Philanthropist


Please follow the code - its there for your safety no matter how inconvenient.
Saturday Cowboy is offline   Reply With Quote
Old 05-27-2011, 09:22 PM   #7
Electrical Contractor
 
Join Date: Feb 2008
Location: Colonia, NJ
Posts: 127
Default

Service mast bracing


Quote:
Originally Posted by WillK View Post
He doesn't like the idea of it breaking and whipping around and hitting the hot conductors, plus he says he'd require one that has a UL listing for the application which he doesn't think there is such a thing.

Personally I'm all for 3/4" tube. I'd be able to do the strength calculations myself if I had to.

I really haven't been able to find any sort of guy wire system in my online searching, aside from some Thomas and Betts stuff that was only available in Canada. I saw some things for antenna applications, and some of the discussions I came across elsewhere made it sound like there's a move away from guy wire support for service masts.
What does your utility co. require?
I don't think that 3/4 EMT is listed for that use.
hpp58 is offline   Reply With Quote
Old 05-27-2011, 10:36 PM   #8
I ask the impossible!
 
Join Date: Aug 2010
Location: Royal Oak, Michigan
Posts: 1,061
Blog Entries: 7
Default

Service mast bracing


POCO requires no support if the attachment point is 30" or less above the roof for 2" rigid conduit. They don't require bracing at all. It's just my inspector that is requiring the bracing because he goes by the weatherhead. Which irritates the heck out of me because as a mechanical engineer, I know that the physics of the pole beyond where the load is applied is irrelevant.

If I had to guess, which is my only option until Weds., his reasoning may be that if I have another 12" of pole available (which I do) then somebody at some future date could move the service attachment up, resulting in the attachment point being above 30".

That being the case, the fact that bracing is unnecessary makes the strength a consideration of secondary importance. The real primary function of installing bracing is that, by attaching it at the service attachment, it keeps the attachment from being moved on the pole.

I guess if I think about it that way, I can also see why guy wire wouldn't serve that purpose since it should be installed with a turnbuckle and hence it could be readjusted in the event somebody wanted to move the attachment point.

I'm probably also overthinking this, but that's in my nature as an engineer.

On the question of EMT being approved for use, I did a search and this was discussed on Mike Holt's forum and their consensus seems to be that EMT without wiring is not covered in NEC. If there is no electrical involved it's just metal tube.

0.042" wall 3/4" tube I believe, which should be able to handle 1500 N of force or 337 pounds. (not sure what grade of steel is used for EMT, so I used the lowest available grade for my calcs) POCO says a 2" riser supports a maximum of 750 pounds of loading. I'd be using 2 pipes in a V for support bracing, so I'd practically be able to support the load with the braces. The braces would never see that load unless the anchors pulled out of the wall, and those are rated for more load each... Geometry plays into it, the bottom line is I could justify not needing the braces to carry load at all.
__________________
Please do NOT consider any "before" picture of my house as any kind of endorsement of any particular construction method. In fact, you should probably assume that if I post a "before" picture, I am posting it because I am soliciting advice on a proper replacement for one of MANY things done wrong by a previous owner.

Last edited by WillK; 05-27-2011 at 11:07 PM.
WillK is offline   Reply With Quote
Old 05-28-2011, 04:14 AM   #9
Member
 
Join Date: Mar 2007
Location: Eighty Four, Pa.15330
Posts: 1,216
Default

Service mast bracing


This needs a picture.
bobelectric is offline   Reply With Quote
Old 05-28-2011, 05:41 AM   #10
Licensed electrician
 
Join Date: Sep 2007
Location: Maryland
Posts: 7,410
Default

Service mast bracing


I think Will needs an inspector with common sense and a code book.

__________________
Answers based on the National Electrical Code. Local amendments may apply. Check with your local building officials.
Jim Port is offline   Reply With Quote
The Following User Says Thank You to Jim Port For This Useful Post:
hpp58 (05-28-2011)
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

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


Similar Threads
Thread Thread Starter Forum Replies Last Post
Service mast questions WillK Electrical 4 04-23-2011 01:24 AM
New service Help (Meter can/ service mast Conduit help) cwolford Electrical 13 03-26-2011 07:55 PM
Wiring Size Calculations for New Service CorinthWest Electrical 7 12-07-2010 11:36 AM
What type of wire for service mast bsperr Electrical 6 01-19-2010 08:53 PM
Service mast options bsperr Electrical 6 12-09-2009 08:48 AM




Top of Page | View New Posts

Copyright © 2003-2014 Escalate Media. All Rights Reserved.