ECN Forum Forums Code Related Discussion NEC & other Code issues wiring tamper switches

triple:

My educated guess of bell box vs. 4 sq is in the cost. I agree with you it would look more professional.

Talking about this today with a job foreman, he had an apprentice use a 1/2" 'C' condulet. The foreman was not happy.

This is the same problem as a solenoid with two or three wires hanging out of a nipple. I use a small GUAB14 for those. Maybe everyone - or someone - would be happy with a larger GUAB16 on a tamper switch? They don't even have mounting tabs.

triple...

The last digital address module that I installed at a tamper switch would absolutely NOT fit inside a one-gang Bell box.

Pinched between two steel locknuts on a GRC nipple, 4 square (deep) fill the bill -- and no-one is willing to toss the $$$ at 2-G WP boxes.

BTW, the labor experience across the trade is that a Bell box takes significantly more time to install than a 4 square... It's hubbed, after all.

It will also then demand a WP cover -- with a gasket -- if not then why the Bell box?

Off the cuff, I'd estimate four times the labor burden.

1) Specialty item -- custom order required -- not ordered by the case

2) Orientation -- hubbed -- an issue

3) Starting the hubbed threads onto GRC nipple -- an issue

4) WP gasket -- a pain -- order spares for the inevitable losses

5) 2-G WP go for about 5-10 times the wholesale price of a deep square. Even the distributor doesn't send them out by the case

6) Threading the cover onto a WP is very substantially slower than a 4 square and its flat cover... with its captive screws

7) Greenfield into a hubbed box is a b234523 and slow going... unless you've ordered the connectors that squeeze from the outside down around the Greenfield. These cost more and are typically a custom order because of that fact.

And, at the end of the day, you haven't improved the robustness of the installed system.

The very isolation of these devices in controlled spaces means that there is nothing and no-one to bump into them.

Thirty-year old boxes just sit there and sit there and sit there.

Once these boxes start falling to the ground -- the AHJ will start changing the installation standards.

BTW, you don't even want to THINK about the non-strapping that occurs in Chicago when the residential boys are running EMT. Local standards there take strapping with in 3' as merely a suggestion.

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You best return on intellectual energy is to dope out elegant, clean, installations -- particularly those that are so commonly encountered.

It's a professional calling that will never end.

Looking at other installations helps a lot, either good or bad or terrible.

BTW, each and every time you run across a terrible installation -- photograph it and up load it to ECN.

All of us here abouts love to look at trashy 'work.'

You don't have to put the module in the box at the valve. Just extend the wires over to a wall.

twh...

AHJ will shoot down ANY splices / make up that is not monitored by the F/A logic.

Extending the leads is EXACTLY what's prohibited.

tesla:
There must be some misunderstanding going on.......

IMHO, the thread is regarding fire sprinkler monitoring devices, flow/tamper. The way I understand it, the 'device' is installed & mounted by the sprinkler guys. The +/- 6" conductors exiting said device are to be extended and connected to the FA system. Be it a LV system, a line volt system it don't matter.

A 4sq locknut mounted to the device was and is the original comment.

John...

You've hit the sore spot.

Such extensions of the tamper leads are against the F/A code.

EVERYTHING in the F/A scheme is supposed to be monitored.

No (additional) field splices are to be introduced by the field crew during the installation.

Should they pull out/ fail there would never be any trouble fault recorded in the system.

Which, in regards tampers, is EXACTLY what an arsonist would do.

The ENTIRE purpose of tamper switches is to frustrate professional arsonists - players that know their way around F/A systems.

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The second you are extending the tamper leads -- you're providing an open shot for an arsonist to gap them open.

After that he'd shut off the valve/ water supply.

Then it's off to the ignition.

When the fire marshall inspects the debris, all that he'd have is an 'innocent' looking gap in the system -- something that the buildings owner could lay off against the original installers.

As you can imagine, the primary employer of arsonists are businessmen.

See: "Who'll Save the Tiger?"

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In short -- extending the tamper leads is forbidden.

We use a 4 wire, monitored system on valves. Opening the leads would create a trouble on the system. How are you wiring your tamper switches?

Every tamper I've encountered had more leads than my (digital) (F/A) module was able to address.

For mass production efficiencies, every tamper is wired up like it's headed off to a chemical plant with a SCADA layout.

My memory is getting pretty lame -- but IIRC -- I was landing only a common (typ. black) and N.C. N.O. leads (typ. red, red w/ stripe) ... with the actual switch festooned with at least two complete sets -- if not more -- and redundant grounding and bonding conductors, too. They were a hair-ball far too big for a 1-G Bell box.

My foremen set the policy: the digital address module was to be deployed right at the tamper switch leads. It was a feather weight plastic device with just enough room to accept labeling.

The F/A cabling for such runs was usually a very sloppy Greenfield whip -- typically daisy-chained from one tamper to the next.

It's been long enough that I can't remember exactly what each maker's module required/ monitored. N.C. or N.O. or both.

I've never encountered a single tamper switch wired in the manner described above... but I haven't seen everything.

Tesla:

Am I missing something, or do you get devices with 'leads' that are long enough to reach the FA panel??

Some of us may be talking about different devices.