Transformer Surge Arrester Voltage Rating

[bcorps]

I have a dual-voltage transformer (4160/12470 primary, 208Y/120V secondary).

The current campus is set up at 4160, but there are plans to upgrade to 12,470 in the near future. That's why they went dual-voltage.

However, the surge arresters on the primary (one per phase), are only 6kV class.

Would it behoove them to go ahead and get 15kV class, or is there some reason to change them when they actually change the voltage?

My understanding is the voltage rating was essentially an insulation class, and higher would be better, but I'm open to learning why it might not.

 

[gar]

210728-1551 EDT

corps:

Ask yourself the question --- what does a voltage surge suppressor do?

Do a search for data sheets on voltage surge suppressors, then look at the current vs voltage curves. Using the word MOV in the search my help find data sheets.

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[gar]

210728-1552 EDT

See https://www.eaton.com/content/dam/e...es/ul-type-1/bus-ele-an-3193-ul-spd-guide.pdf
page 41 for a plot of voltage vs current.

When you change the nominal applied voltage to a voltage suppressor you will need change to a different voltage rating suppressor.

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[bcorps]

Okay, thanks. I will just have to remember that when they change the feed to the transformer to 12,470...they'll have to change the arresters too. There's no "future proofing" that can be done at this time.

Much appreciated.