Thread: Electrical Roof Mast

Can someone tell me what height the roof mast has to be before it has to have a cable attached to it

Jim Murphy

South Carolina

Most times that is determined by the local power company rules and is available in their design guide.

If the mast is leaning toward the overhead service drop, and especially if the mast is bent, then ... then it needed tohhave been supported and now needs to be replaced.

Originally Posted by Jerry Peck

If the mast is leaning toward the overhead service drop, and especially if the mast is bent, then ... then it needed tohhave been supported and now needs to be replaced.

I understand that Jerry but this is a new mast and it is at least 4 feet from the surface of the roof. Overtime, I feel like it will be a problem

Jim

Jim,

It's not just the unsupported height of the mast, it is also how well anchored the lower part of the mast is, how long the lower part of the mast is, and how long the overhead service drop is - among other things.

A 4 foot tall mast with a short overhead service drop length is likely not a problem if all below it is long enough and well supported; however, that same mast with a long overhead service drop may need to be supported.

Likewise, the service drop coming off a tall pole doesn't pull as much on the mast as a service drop coming off at a lower height does.

I am not in my office right now, but a Google search for overhead service mast height may find some information which may give a good idea of typical heights which need to be supported. Just a thought, I'll check a little later when I am in my office.

Originally Posted by JIM MURPHY

I understand that Jerry but this is a new mast and it is at least 4 feet from the surface of the roof. Overtime, I feel like it will be a problem


Jim

One utility in Ct here says "service mast 2" min galvanized steel or 2 1/2" min aluminum conduit unless supported by guys or braces per NEC sec 220.28. That section just talks about adequate strength or it should be supported with guys or braces. I think an inspector told me once over 3' he wanted a guy, but that was his own thing. If it's 2" ridgid conduit and a typical drop of 75' or less I think you're fine.

Originally Posted by Gerry Bennett

One utility in Ct here says "service mast 2" min galvanized steel or 2 1/2" min aluminum conduit unless supported by guys or braces per NEC sec 220.28. That section just talks about adequate strength or it should be supported with guys or braces. I think an inspector told me once over 3' he wanted a guy, but that was his own thing. If it's 2" ridgid conduit and a typical drop of 75' or less I think you're fine.

Thanks Guys. The piling is a rigid 2" pipe so i am going to let it slide. In my gut, it just looks too tall.

Jim

In snow country with trees around, I would call it out. I have seen a few bent masts that bent from the extra weight of a tree branch and a foot of wet snow.
So they were good without a guyline for a while, but bad now and an expensive repair.

A better than average roofer created a guyline flashing I want to share. See the pic, a lead boot for a plumbing vent, crimped around the guyline.

Originally Posted by JIM MURPHY

Thanks Guys. The piling is a rigid 2" pipe so i am going to let it slide. In my gut, it just looks too tall.
Jim

It is "minimum." So if it still bothers you, call it out as something to have checked. It's better to say something now, than later wish that you did.

Originally Posted by John Kogel

In snow country with trees around, I would call it out. I have seen a few bent masts that bent from the extra weight of a tree branch and a foot of wet snow.
So they were good without a guyline for a while, but bad now and an expensive repair.

A better than average roofer created a guyline flashing I want to share. See the pic, a lead boot for a plumbing vent, crimped around the guyline.

"call it out"? It is legal if it is approved by the Utility and by the inspection code at time of intallation.
So your going to write... daaa I think Their wrong...?

Originally Posted by John Kogel

In snow country with trees around, I would call it out. I have seen a few bent masts that bent from the extra weight of a tree branch and a foot of wet snow.
So they were good without a guyline for a while, but bad now and an expensive repair.

A better than average roofer created a guyline flashing I want to share. See the pic, a lead boot for a plumbing vent, crimped around the guyline.

Originally Posted by bob smit

"call it out"? It is legal if it is approved by the Utility and by the inspection code at time of intallation.
So your going to write... daaa I think Their wrong...?

Sorry Bob,

There is No Way in all the History of Electricity that a lead plumbing vent boot morphed into a guide wire anchor was ever "legal."

Looks to me like the "boot" covers the hardware that penetrates the roof to anchor the cable. What's not legal about that? Probably will outlast any tar-like material that would have been used to do the job otherwise.

FWIW, around here the mast height above which there has to be a cable is 48" above roof to top of weather head, spec'd in the utility service standards book. A cable can be required by the utility for shorter masts in various conditions.

Originally Posted by bob smit

"call it out"? It is legal if it is approved by the Utility and by the inspection code at time of installation.
So your going to write... daaa I think Their wrong...?

I would call it out in my own way. I will never say that it is not legal, because someone with authority, like you, already has signed off on the installation, as you say. You made it 'legal', but it might be in need of maintenance now, a few years later.

If the pipe mast is tall, with a long service drop cable running under tree branches, I would 'recommend' or 'advise' the simple addition of a guyline. What is the problem with that?

I would also call for the overhanging branches to be cut. They were smaller at the time of the installation, most likely, or not even there.

Here's something I saw last fall. Service thru the trees to a tall mast. Power company installed a new pole on the road. New pole is taller. Dumbass pulled the service drop up to make the new connection. He used a come-along, no doubt. Now the house has service in contact with tree branches, and a bent mast.

Originally Posted by Bill Kriegh

Looks to me like the "boot" covers the hardware that penetrates the roof to anchor the cable. What's not legal about that? Probably will outlast any tar-like material that would have been used to do the job otherwise.

FWIW, around here the mast height above which there has to be a cable is 48" above roof to top of weather head, spec'd in the utility service standards book. A cable can be required by the utility for shorter masts in various conditions.

Gosh I can't ( didn't think even Superman could ) see through Lead.

I have not encountered any specs as to how, material, or methods to employ 'when' mast support is required by the utility or inspection authority.
As an AHJ, this piticular support appears to be of a more good faith attempt than most.
Of course, as a HI you can can suggest/offer your opinions in your reports.

Originally Posted by bob smit

I have not encountered any specs as to how, material, or methods to employ 'when' mast support is required by the utility or inspection authority.
As an AHJ, this piticular support appears to be of a more good faith attempt than most.
Of course, as a HI you can can suggest/offer your opinions in your reports.

Sorry Bob but the Utility Provider is the AHJ on this one and I don't see them penetrating a Residential Roof to install a service drop. So it's gotta go.

Mast support requirements are commonly in the poco design manuals and commonly available online with diagrams.

Originally Posted by Billy Stephens

Gosh I can't ( didn't think even Superman could ) see through Lead.

Absolutely right! Neither one of you can.

Originally Posted by Bill Kriegh

Looks to me like the "boot" covers the hardware that penetrates the roof to anchor the cable.

Originally Posted by Bill Kriegh

Absolutely right! Neither one of you can.

I never claimed to have "that power".

Originally Posted by Billy Stephens

I never claimed to have "that power".

There's no Superman spandex under the white and gold jumpsuit? I'm disappointed.

The roof was new. The guyline was old. I'm pretty sure the roofer split the lead boot and wrapped it around the old existing eye-bolt. I think he did a super job of it.

Originally Posted by John Kogel

There's no Superman spandex under the white and gold jumpsuit? I'm disappointed. .

I might have slowed down a bit and put on a couple lbs. of late.
*but I still plenty Ballsy.

Originally Posted by John Kogel

The roof was new. The guyline was old. I'm pretty sure the roofer split the lead boot and wrapped it around the old existing eye-bolt. I think he did a super job of it.

You mean the guyline that was put on after the un permited service mast extension and addition was built.

Yeah, that's the old pic I was thinking of, back then the hair was still natural, eh?

And stick another prop under the balcony. There's gonna be a hot tub party, and I hear it's at your place.

Originally Posted by Billy Stephens

Sorry Bob but the Utility Provider is the AHJ on this one and I don't see them penetrating a Residential Roof to install a service drop. So it's gotta go.

No need to apologize Billy.
The utitlity & the area electrical inspector are the AHJ's, and we do collaborate. Either authority can reject an installation even if approved by the other.

You're free to call this one out if U wish. Then POCO & myself are notified and in this case, we will just shake or heads and laugh.
No need to apologize.

Originally Posted by bob smit

No need to apologize Billy.
The utitlity & the area electrical inspector are the AHJ's, and we do collaborate. Either authority can reject an installation even if approved by the other.

You're free to call this one out if U wish. Then POCO & myself are notified and in this case, we will just shake or heads and laugh.
No need to apologize.

Thanks for your Permission Bob.
*After you approve the shown installation ( service line touching the roof ) I hope your pompous Arash at least gets fired if not Criminally Prosecuted.

Originally Posted by John Kogel

Yeah, that's the old pic I was thinking of, back then the hair was still natural, eh?

Jheri Curl BABY!!!

And stick another prop under the balcony. There's gonna be a hot tub party, and I hear it's at your place.[/QUOTE]

..Under Construction as We Speak.