Mast Service

[stevebea]

I have a mast service to install that the service head will be about 3 ft. above the roof line to keep my clearances on the service drop conductors. Per POCO requirements my mast will needed to be guyed to the roof. Any recommendations? Any trick parts out there that would work well for this application? Thanks.

 

[220/221]

Your POCO will have their own requirements.

Here in the desert, we use 3/4 EMT, bolted thru the rafters.

With 2" IMC, we can go 30" or 36" above the mast brace to the POA before back bracing is required. If we use 2.5" IMC, we can go to 50"

 

[readydave8]

Here in the desert, we use 3/4 EMT, bolted thru the rafters.

Do you run a EGC in that emt?

 

[hbiss]

Here in the desert, we use 3/4 EMT, bolted thru the rafters.

That's a great concept. Do you fabricate it yourself? Looks that way and if so it looks like a great opportunity for someone to invent clamp type fittings that would allow attachment of the EMT braces to the mast and roof without flattening the ends and drilling.

-Hal

 

[stew]

there is a kit available to use with rigid or IMC that has threaded collars with ears on them and a matching clamp on the mast that work very nicley for this.

 

[lakee911]

Your POCO will have their own requirements.

Here in the desert, we use 3/4 EMT, bolted thru the rafters.

With 2" IMC, we can go 30" or 36" above the mast brace to the POA before back bracing is required. If we use 2.5" IMC, we can go to 50"

Are those box covers attached to the roof? Are they listed for that purpose?

Why are the conductors of the two legs of the service drop white? I think that PUCO could get away that, but I've personally seen black.

I also like the messenger wire wrapped around the pole...

 

[renosteinke]

Check with your supply house; chances are that they have a 'mast kit' for just this purpose.

In my case, the kit is designed to let you use 3/4 RMC or IMC as the brace material. The 'feet' are attached to the roof with lag bolts.

As for the wire in the picture .... chances are that the wire insulation is actually grey. There was a supplier that sold loads of this stuff to Western utilities - only to have the stuff begin flaking apart after a few years. PoCo's are scrambling to replace it.

When you do a service upgrade, it's very possible that the old PoCo hardware will not fit the new mast. PoCo's are also changing their rules; some that once allowed the EC to disconenct . reconnect the lines no longer do. I suspect that this is the case for the job in the picture. Otherwise, the fittings for attaching the ACSR to the mast, and for connecting the wires together, are likely supplied by the PoCo.

 

[220/221]

That's a great concept. Do you fabricate it yourself?

Yes. .

As far as manufacturing them, the length varies with every installation so we just make them as needed

Do you run a EGC in that emt?

Are those box covers attached to the roof? Are they listed for that purpose?

Why would hardware like that need to be listed? It's just a big washer. It's the first time I've used this method and I like how it turned out. Very sturdy and roofers can work around it when reroofing (soon in this case). There is a nut under the EMT

Usually we just drill and bolt thru the flattened portion of the EMT and seal over it. Creating a seperate attachment point just seemed like a better way to do it. It also keeps the EMT from digging in to the shingles. There is also sealant under the plate.

Why are the conductors of the two legs of the service drop white?

Gray

I also like the messenger wire wrapped around the pole

Temp. I needed to get it our of my way and it was too damn heavy to get it wrapped around the POA.

I suspect that this is the case for the job in the picture

Yeah. POCO here doesn't want us touching their stuff. The linemen don't care, the lawyers do.

 

[jaylectricity]

Not to thread-jack, but how do I find out the requirements for masts and supports? I'm looking at 230.28 (nec2008) and it says "it shall be of adequate strength or be supported by braces or guys to withstand safely the strain imposed by the service drop."

My situation is 21/2" rigid metal conduit, it rises about 5 feet above the roof (pitched at close to 45 degrees), roughly 50 feet from nearest telephone pole (or mid-span more accurately). Seems like it will be adequate strength, but how can I know for sure?

 

[renosteinke]

I found the mast support requirements to be far more specific, and with helpful artwork, in my PoCo's standards.

PoCo standards are something every EC should have. The good news is that most PoCo's have them available, for free, through their web site.