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#129768 - 08/10/05 04:02 PM Intermatic AG2401 Surge Protector & MOV Quest.
Robert11 Offline

Registered: 08/05/05
Posts: 10
Loc: Boston, MA

Was wondering if anyone has ever used the "point of use" (secondary type) Intermatic AG2401 model surge protector ?
If so, opinions on ?

It supposedly clamps at 490 V.

This seems to me awfully high, and possibly above what many solid state components and microprocessors would possibly be destroyed at.

Do you think it (still) would provide adequate protection and be worth installing ?

Any thoughts on this, or recommendations, perhaps, on similar units that clamp lower ?

BTW: when having worked within their limits, are typical MOV's usually good for many such clampings, or do they degrade quickly, even if the clampings were "nominal" ?

Much thanks,

#129769 - 08/16/05 03:38 AM Re: Intermatic AG2401 Surge Protector & MOV Quest.
Trumpy Offline


Registered: 07/05/02
Posts: 8532
Loc: SI,New Zealand
What exactly are you trying to protect?.
It supposedly clamps at 490 V.

There are 2 different forms of Surge Protection
  • Coarse- Gets rid of most of the Surges that could hurt your Electrical system.
  • Often uses plug-in modules, fitted in the panel.
  • Once the plug-in module is spent, that's it.
    Other side of the coin and the most important:
  • Fine protection- Local protection of all electronic devices.

Lightning surges work on what is called a 8/20 uS Surge.
Let's face it, these days if you're not young, you're old - Red Green grin

#129770 - 08/16/05 04:29 AM Re: Intermatic AG2401 Surge Protector & MOV Quest.
Robert11 Offline

Registered: 08/05/05
Posts: 10
Loc: Boston, MA

Thanks for help.

Have a new hot air furnace by Trane whose circuit board was fried during a recent lightning storm.

Have a very old electrical service box, and for a variety of reasons (no spare ckt breakers or room for new ones)I cannot install a "whole-house" surge protector at the service box. These require to two free ckt breakers which I don't have.

For now, it looks like the only reasonably practical approach is to put one of these Intermatic units in right next to the furnace, on the AC line going to it.

The 490 V clamping volt., however, bothered me. Seems a bit high; what do you think ?

What is this 8/20 us Surge spec., please ?
Have never heard of it.

Any other thoughts ?

Thanks again,


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