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Joined: Dec 2001
Posts: 444
Sandro Offline OP
Hello.....on a recent job the homeowner asked that I install this device...

Here is the question..... I have a 400 amp main switch and 2-100 amp panels and a 200 amp panel feeding off a splitter.

If I parallel this device off the 400 A splitter will it do its job properly? Or is it recommended that he pick up a unit for each individual panel?

The literature says that this thing can only handle max 100 amps in series, but I'm wondering about 400 amps in parallel?

Any tips or advice would be appreciated.


Joined: Apr 2002
Posts: 2,527
Apologies—the meaning of the term “splitter” is not apparent. Assumed it’s used to establish taps.

Read the surge-arrester literature carefully: "Wiring Feed-through dual lugs rated 100A maximum continuous line current using #3 AWG conductors"

So, no—it looks like it won't work as claimed unless ‘loop through' is used. [Get it in writing from the TVSS manufacturer if there’s any question of this.]

Think you'll find that a "Kelvin" connection is required to meet their advertised capabilities, and as such, only suitable for a 100-ampere-maximum circuit. Likely too are that separate raceways must be installed for incoming and outgoing conductor bundles; id est, a single-nipple connection to the TVSS containing all conductors is probably verboten if one wants to preserve the published ratings of the device. [Heed manufacturer’s ground-conductor instructions and routing to the letter.]

You may want to install three of the subject devices—two for the 100-amp panels connected in ‘loopthrough,’ and one in a non-looped/tapped arrangement for the 200-mp panel, understanding that the suppressor will not be as effective in this mode.

If the building owner still insists on this particular device then point out the deficiency, get paid, and walk away.

Joined: Apr 2002
Posts: 914
I've never used this model before, usually I use a Sq D SurgeBreaker or SurgeBreaker Plus(for cable and phone also). But anyway, the specs say it can be located at the main service disco, so if you install it before the "splitter" it should protect all panels. If that can't be done, then I think you need one on each panel(unless one is a sub of another).

Joined: Jul 2002
Posts: 175
We call this type of tap box a "splitter" in Canada. What term do you use for them?

[Linked Image from]


Joined: Apr 2002
Posts: 2,527
There’s these, but they are only UL-component recognized, so it’s arguable their applicability under NEC 370/374.,40.pdf I like these with hydraulic-compression terminals in industrial/research facilities, but building inspectors would have a fit. In a research environment, made a lot of larger versions with copper-bar stock, silicon-bronze studs, silver solder and Glastic knobs, but there’s those pesky inspectors almost everywhere.

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