Secondary Surge Arrester

http://www.nooutage.com/images/La302r_small.jpg http://www.nooutage.com/images/spec-sheets-thumbnail.gif

AC Residential Surge Arrester
125/250Vac, single phase, 3-wire

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**Features

  • Locknut and bushing furnished for simple mounting.
  • Extra long 36" #12 THHN leads for ease of installation.
  • Will pass a large number of high-energy surges and half-cycle spikes prior to failing.
  • Always fails “clear” to permit continued use of power system.
  • Non-conductive base to prevent a blown arrester from being a shock hazard.
  • Will not produce carbon dust upon failing like some other arresters, preventing
    damage to other equipment
  • 4-1/4" high, 2-1/4" diameter
  • PVC weatherproof case
  • Locknut and washer furnished
  • UL Recognized
    Simple to install on outside of load center panel, or inside.
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Looks double tapped to me.

Must be a geographic thing. I’ve never seen them anywhere but the main…

Interesting…the Square D installation instructions say the wires should be short.

WHERE’S PAUL?? WHERE’S MARC SHUNK? HELP!!!:wink:

They should be short to reduce inductive resistance.

tom

The ones I have installed say they must be on the load side of a 240v breaker.
My main concern with the double tap is the size and type of the lead. I doubt the SqD and CH breakers are listed for a #10 solid and trhe smaller stranded you get on the protector. I had the slots so I put mine on a separate 20a double pole.

Which answers my earlier question…

You apparently CAN put this on an unused breaker by itself. Do I understand that correctly?

Thanks,
Bruce

It would have to be a two pole breaker to be effective for both “hi” sides.

Right, sorry. Shoulda clarified.

Here’s a site with various installation arrangements:

http://www.deltala.com/installa.htm

From a purely engineering protection point-of-view it really doesn’t matter where it is connected as long as the wires are kept relatively short (because of industance as mentioned above) and the device is connected to both busses (i.e. via the SE lugs or 2 pole breaker). Note that curling the long wires into a coil to keep them “short” would about the worst thing to do.

The main reason that the usual recommendation is to connect thorough a breaker is because often, when a surge arrestor does its job (or tries to), it typically fails at the same time and will need to be replaced. Most of the time I would expect it to fail “clear”, thus the need to be able to see the light. If the failure mode is really severe, it will trip that breaker. A connection at the SE lugs would mean having to de-energize the entire panel, often with the assistance of the local utility.