Hello:



Will be putting in a "secondary" wired in surge protector (an Intermatic AG
2401 IND )

to try and protect a new furnace circuit board that is apparently
susceptible

to lightning induced transients. It fried during last lightning storm.

Eventually, I hope to replace the electrical service box, and, when I do, I
will install

a whole-house variety. But for now, will have to settle for the
point-of-use, wired in variety.



There is the typical on/off furnace switch located in a EMT tubing run,
about a foot or so from the furnace proper. This seems like a good place to
wire it in, and install it.



Have been thinking a bit about whether it makes more sense to wire it in on
the upstream side of the switch, or whether it should be placed on the
downstream side (the end closer to the furnace) ?



Seems to me that it probably doesn't matter at all, but thought I'd ask.



Any thoughts on ?



Thanks,

Bob

"Robert11" wrote in message
...
Hello:



Will be putting in a "secondary" wired in surge protector (an Intermatic
AG 2401 IND )

to try and protect a new furnace circuit board that is apparently
susceptible

to lightning induced transients. It fried during last lightning storm.

Eventually, I hope to replace the electrical service box, and, when I do,
I will install

a whole-house variety. But for now, will have to settle for the
point-of-use, wired in variety.



There is the typical on/off furnace switch located in a EMT tubing run,
about a foot or so from the furnace proper. This seems like a good place
to wire it in, and install it.



Have been thinking a bit about whether it makes more sense to wire it in
on the upstream side of the switch, or whether it should be placed on the
downstream side (the end closer to the furnace) ?



Seems to me that it probably doesn't matter at all, but thought I'd ask.



Any thoughts on ?



Thanks,

Bob



Don't you want to installed it way, way upstream where the breaker panel is?
That would protect your house wiring insulation as well. With lightning
where the transient is in the nano second range (super fast) anything could
happen and surge protection is not 100% guarantee. Transient will seek a
path to you furnace circuit board, or anything else, in the most
unpredictable manner in a worst case scenario. In any case, make sure you
have a good house ground, circuit board ground plane is solidly grounded and
disconnect the main breaker during the next big lighting storm if you could.

It's definitely preferable to have it at the service panel with as
short a run to an earth ground as possible. That will not only protect
the whole house, but also do a better job of protecting the furnace as
well. The longer and more resistance in the ground path, the less
likely the surge protector will succeed in shunting a surge.

If you do go with one located at the furnace, either side of the switch
should provide the same protection for the furnace.