Close Call

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Close Call

Post  336arod on Tue Apr 02, 2013 9:25 pm

We had a close call today, a 2 man crew was doing switch maintenance (first time in 14 years) and made contact phase to ground on a feeder, 636 acsr with approximately 500A per phase on the circuit at the time. I wasn't there but from what I understand it was quite a flash. The FDR was on non-auto. The switch maintenance consisted of bypassing the switch with a MAC test operating and lubricating. The switch was relatively new, 80's vintage, gang setup assembled from the factory on a fiberglass arm. This is the second instance that I'm aware of in our system where the metal hardware on the fiberglass arm of the switch is grounded to both the nuetral and the pole ground, which makes a direct path to the switchman. I'm wondering if this was common practice back then, or if the lineman/engineers at the time didn't install it to spec. What's the point of a fiberglass arm if you ground everything on it? The lineman was using a MAC that was a little short for the job so he was attempting to attach it to the jumpers on each side of the switch. We are a sticking company, he attached one side of the MAC to the jumper between the shoe and the switch (which was slack), the other end of the MAC was on a bolt attached to the MAC ferrell already on the line, in attemtping to pull the other ferrell off the first one he brushed the metal extension link between the fiberglass arm and the insulators, the switch hardware was grounded, hence the arc and lockout. He was not injured aside from some minor arc induced sunburn.

336arod

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Re: Close Call

Post  MI-Lineman on Wed Apr 03, 2013 9:57 pm

I have no answer for you on this but am glad everyone's alright!


Last edited by MI-Lineman on Sat Apr 06, 2013 4:56 pm; edited 1 time in total
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Re: Close Call

Post  Bluestreak on Thu Apr 04, 2013 7:32 am

Most new switches installed in our area have arresters installed on the switch meaning there are grounds right on the switch, that being said work practice requires 2 lineman in the air when jumpering switches or taps typically a insulated mac long enough to reach out away from the switch and the stuff hanging off it,

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Re: Close Call

Post  lewy on Sat Apr 06, 2013 8:43 am

Ya sounds like there should be 2 guys in the air, glad he's alright. What size jumper were you using or were you going to use more than 1 to carry that kind of load?

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Re: Close Call

Post  336arod on Sun Apr 14, 2013 1:23 am

I agree there should been two guys in the air, also should have been using a longer Mac. A longer Mac wasn't available or the other guy... Classic example of shortcuts taken to maintain production, everything's good until something goes wrong. The Mac was 4/O copper, which is also to small but probaly would've worked for the time frame, but would most likely cause voltage problems.

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