The surge suppressor in the link looks a bit cheap and small for a whole
house. I would think something like that should be put inside a grounded
metal box to contain the fire and sparks
----- Original Message -----
From: "Jim Thomson" <firstname.lastname@example.org>
Sent: Monday, 03 January, 2011 7:11 AM
Subject: [TowerTalk] Whole house surge suppressor's.
> Hi Dale.
> I've been in the fire service for 27 years now and I can't tell you the
> number of surge suppressors of the type that are typically installed on
> a 1/2" or 3/4' knockout hole*http://tinyurl.com/2cpxn7a *that created
> the structure fire that we were responding to. On a couple of
> occasions, I've seen them violently shoot green flames out of them in
> every direction as they burned themselves to a cinder.
> My power company installs the meter base style suppressor which places
> it outside of the structure the majority of the time. I'm sure that's
> probably what you're also looking at.
> Jon Pearl - W4ABC
> ## The Joslyn brand surge protector's are used by the 10's of thousands
> by telco's across NA.
> They are mounted below, or close by a main panel. Conduit between main
> panel + protector.
> The protector's we used at work, were all in steel enclosures, and those
> things were latched
> shut tighter than a drum. Each of the two [ 3 movs used for 3 phase]
> huge movs are wired
> between hot and neutral [ ditto with 3 -phase]. Each mov had a 20A slow
> blow fuse in front of it.
> [600V rated... big cartridge fuses.. like the .375" to .5" x 2" long
> Output of each fuse feeds a neon. Output of neon wired to same neutral.
> A 4pdt relay..with a 120 vac coil
> is also used... one per mov. 120 vac coil wired between output of fuse
> and neutral.
> ## OK, with everything normal, all the neons are lit green. If one or
> more MOV's shorts out, the mating fuse
> that feeds it blows open asap, and MOV is now out of the circuit.
> Associated neon also goes dark. Mating
> 120 vac dpdt relay also drops out..... bringing in an alarm to the alarm
> center/NOC etc. All the relay's of course,
> in normal operation, are always operated 24/7..... except when a mov fuse
> blows open.
> ## I never saw one of those joslyn protector's ever catch fire in 34 yrs
> I was there. [ no equipment failures from
> lightning, transients/spikes/surges either]. As long as they are fused
> I don't see how the mov could burst into flames. Even if it did, none of
> it would get past the steel box. Those box's
> were sealed very good, with a pair of real heavy duty latchs. They were
> not like a regular steel electrical box either.
> These things were water proof, fire rated nema box's. The seal design
> was the best yet. If they were the slightest fire hazard,
> the insurance co would have been reading us the riot act. [ factory
> mutual in the US is the main insurance co for most of the telco's
> in the usa + canada.] In some parts of Florida, etc, home insurance co's
> will insist that whole house protector's are employed.
> Insurance co's were getting tired of paying out claims in lightning prone
> ## I have seen some of the whole house protector's..sold at home depot
> etc.. that use way smaller mov's.... and contain
> no internal fuses... but use a spare 40-60A breaker position on the main
> panel. The box's they use look flaky to me. They also
> use plane romex, etc, from main panel to plastic box... and no conduit.
> Later... Jim VE7RF
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