# Service Mast



## electricguy (Mar 22, 2007)

Franklingower said:


> A Service Mast is vulnerable to over tension of the line to the pole or, most often, the line is hit by a fallen tree branch.
> The attachment is my opinion as to the case of most mast failures.


Thanks


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## PlugsAndLights (Jan 19, 2016)

Franklingower said:


> A Service Mast is vulnerable to over tension of the line to the pole or, most often, the line is hit by a fallen tree branch.
> The attachment is my opinion as to the case of most mast failures.


Fallen branches for sure. Do see much damage from ice as well? 
P&L


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## Navyguy (Mar 15, 2010)

I am not sure how you came up with your numbers, but in your last drawing, you have 59", which is the measurement from the last clamp. The code requires a support (guy) if the mast is 39" or more above the roofline.

So there are two options for this:

1 - if you have a "thin" roof you maybe within the 59" from the top clamp but more then 39" above the roof line and will require a guy; or
2 - if you have a "thick" roof where you might be more then 59" from the last clamp but less then 39" above the roof line, you still need a guy wire.

The only time you do not need a guy wire for support is if you are less than 59" from the clamp and you have less than 39" above the roof line.

Your pictures look to me that there was a lot more than 39" above the roof line and I could not see the guy wire. All of this is for not, if the guy wire is not located and fastened properly anyway, it simply becomes just a decoration...

Not sure if what I have said changes your numbers?

Nice to see some science behind our codes though...

Cheers

John


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