# 4.16KV Primary Surge Arrestor



## Meadow (Jan 14, 2011)

I would defiantly add suppressors on the transition risers, right before the cutouts is doable but its a trade of between less protection with less chance of nuisance fuse blowing. 

Pad mounted elbow suppressors can be optional, but a good idea to have.


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## Big John (May 23, 2010)

There's no set standard. But I don't typically see elbow arrestors used as a replacement for overhead: The advantage to the pole-top arrestors is that otherwise the high impedance of the underground cable causes the insulation to be exposed to a much more severe voltage rise as the surge impulse propagates down the cable length. 

Overhead arrestors typically experience much more severe discharge current for exactly this reason, even when they're on the same circuit as the elbow arrestors, because they see that higher voltage peak before it reaches the transformer.

Short answer: If you made me pick one, I'd pick overhead. But doing both is definitely the best install.


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## Meadow (Jan 14, 2011)

Big John said:


> There's no set standard. But I don't typically see elbow arrestors used as a replacement for overhead: The advantage to the pole-top arrestors is that otherwise the high impedance of the underground cable causes the insulation to be exposed to a much more severe voltage rise as the surge impulse propagates down the cable length.
> 
> Overhead arrestors typically experience much more severe discharge current for exactly this reason, even when they're on the same circuit as the elbow arrestors, because they see that higher voltage peak before it reaches the transformer.
> 
> Short answer: If you made me pick one, I'd pick overhead. But doing both is definitely the best install.


:thumbup::thumbsup:

What he said


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## JW Splicer (Mar 15, 2014)

Big John said:


> There's no set standard. But I don't typically see elbow arrestors used as a replacement for overhead: The advantage to the pole-top arrestors is that otherwise the high impedance of the underground cable causes the insulation to be exposed to a much more severe voltage rise as the surge impulse propagates down the cable length.
> 
> Overhead arrestors typically experience much more severe discharge current for exactly this reason, even when they're on the same circuit as the elbow arrestors, because they see that higher voltage peak before it reaches the transformer.
> 
> Short answer: If you made me pick one, I'd pick overhead. But doing both is definitely the best install.


I think it's called the voltage doubling effect?


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## Big John (May 23, 2010)

JW Splicer said:


> I think it's called the voltage doubling effect?


 I didn't know it had a name. Thanks, I'll do some reading.


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