Why is a leaning electrical service mast dangerous?
Wednesday, May 12, 2021
When the structural integrity of a service mast begins to fail and it leans further and further over—pulled by the weight of the service cables, with the mast as a lever—it can eventually rip the meter lugs from the insulator mounts and leave them dangling. An electrical short will often follow and, unfortuanately, there is no overcurrent protection at most electric utility meters. They are designed to withstand a large current surge, but not to stop one. The main breaker for the home is downstream and will not be triggered, so an electrical fire comes next.
Here’s an example above of an electrical fire at a meter, one that was caught in time. It had a different configuration (underground service) and different cause (cable short between meter and service panel), but is an example of what can happen quickly with a short at a meter that does not have overcurrent protection.
There’s also a secondary problem caused by the openings of the leaning service mast at connections that let rainwater run down into the meter box, corrode the interior, and damage the meter equipment.
So the moral of this tale is: don’t wait too long to fix a leaning overhead service drop. Also, here’s a few of our other articles about electrical service drops: What is the minimum overhead electric service drop height/clearance to a house? and Can anything else be attached to a service mast for overhead electric service besides the service cables? and What is the electrical "service point" of a house?
Thanks to Craig Eaton for help with this article.
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