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#215098 - 03/03/15 06:01 PM wiring tamper switches
triple Offline
Member

Registered: 04/01/02
Posts: 182
Loc: Wisconsin
In my area, sprinkler system tamper switches are always nippled to a standard 4-square box that simply dangles unsupported. This provides a junction point for the short lengths of wire leaving the tamper switches before being flexed to a nearby point in the fire alarm system. No AHJ has ever had a problem with this installation. I'm curious as to how this situation is handled elsewhere. Are hubbed boxes used as a better means of support by its connection via the nipple to the switch?

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#215099 - 03/03/15 06:36 PM Re: wiring tamper switches [Re: triple]
Tesla Offline
Member

Registered: 06/16/04
Posts: 1280
Loc: Sacramento, CA
Nope.

I've installed all of my F/A systems in exactly the manner described in the original post.

The NEC is oriented towards fire hazards.

The weight of the trivial materials tucked inside such junction boxes is a joke.

If ANYTHING goes awry -- the F/A system goes into ALERT mode -- which is not the same as an alarm.

In ALERT mode the system informs the dispatcher to promptly send out a tech to service the system. The modern, digital, systems will even point out the faulting address.

If, at any time, a bona fide fire / emergency occur, the system will fire off into full ALARM mode -- over-riding the ALERT mode.

EVERY F/A system uses this priority sequence. No system is allowed to fault out -- and fail to notify the dispatcher and those inside the structure.

&&&

You're actually over engineering your scheme... a fault common to electricians the world over.
_________________________
Tesla

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#215100 - 03/03/15 07:13 PM Re: wiring tamper switches [Re: triple]
twh Offline
Member

Registered: 03/11/04
Posts: 892
Loc: Regina, Sask.
I always nipple the box to the switch. It isn't what I would describe as "dangle."

FWIW, in Canada we have a rule: "12-3012(2) Boxes and fittings having a volume of less than 1640 ml shall be permitted to be attached to a firmly exposed raceway by threading or other equally substantial means." I always thought a nipple on a tamper switch was firmly secured.

Do you have a similar rule in the NEC?

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#215141 - 03/08/15 03:08 PM Re: wiring tamper switches [Re: triple]
triple Offline
Member

Registered: 04/01/02
Posts: 182
Loc: Wisconsin
1) Occasionally, 120v is fed through a tamper switch (even in a modern system). Surely an unsecured, standard box can not be accessible in that scenario.

2) Many AHJ's would not allow an unsecured box for control wiring which is also a low voltage/signal system.

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#215147 - 03/09/15 01:38 PM Re: wiring tamper switches [Re: triple]
Tesla Offline
Member

Registered: 06/16/04
Posts: 1280
Loc: Sacramento, CA
1) Occasionally, 120v is fed through a tamper switch (even in a modern system). Surely an unsecured, standard box can not be accessible in that scenario.

&&&&

I've never seen such a scheme.

Let's narrow this discussion down to just fire alarm systems.

Then the only 120V circuit routinely encountered is a FIRE BELL initiated by the FLOW SWITCH in the F/A MAINS.

Typically, this device trips two parallel, yet independent, switches.

Both are situated on a cam-assembly that rocks/ torques when the flow gets rolling/ or some lever arm.

The 120VAC -- low amperage device -- fires of an 'idiot-simple' fire bell immediately outside the (sprinkler) riser room.

At the same moment, the fire alarm does its thing -- with low voltage logic. (Typ 24VDC to 34VDC -- most set at 28VDC)

The notification appliances receive a reversed polarity -- and are off to the races.

I've NEVER seen the elaborate work-up you are speculating upon here.

As for the 120 VAC bell, there is a special exclusion in the NEC that permits that whip to run in #18 wire. Even after I pointed this out, my field superintendent had me upgrade this whip to #12.

As loud as these bells are, they use practically no current.

They are also a belt & suspenders cure, for the F/A system is making a terrible racket as it is -- as well as notifying the local responders.

&&&&&&&

F/A is not considered control wiring. It's considered a LIFE SAFETY circuit. It even has its own code rules, most of which are entirely outside the NEC, for what it's worth.
_________________________
Tesla

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#215148 - 03/10/15 09:12 AM Re: wiring tamper switches [Re: triple]
HotLine1 Offline

Member

Registered: 04/03/02
Posts: 6785
Loc: Brick, NJ USA
triple:

Are you saying the 'box' is connected to a nipple of the flow switch, and that the box has NO other mechanical means of support??
_________________________
John

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#215150 - 03/10/15 08:54 PM Re: wiring tamper switches [Re: triple]
triple Offline
Member

Registered: 04/01/02
Posts: 182
Loc: Wisconsin
That is correct HotLine1. A standard 4-square held in place by a locknut.

The job I am on right now provided two different outside fire alarm bells to pick from (probably a screw up). One of them was 120v and schematically showed that 120v being switched through the main flow switch. That is the type of box that I DEFINITELY can't imagine not being securely mounted.

In my view, the fact that the fire alarm panel will notify you of an open or short seems like a poor reason to allow an unsecured box. Should we also allow such workmanship for line voltages as long as the item in question is monitored/protected by both gfi and arc fault?

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#215153 - 03/11/15 08:18 AM Re: wiring tamper switches [Re: triple]
Tesla Offline
Member

Registered: 06/16/04
Posts: 1280
Loc: Sacramento, CA
triple...

The TYPICAL flow switch is installed by the sprinkler boys.

It's TYPICALLY inside a robust housing...(red) that's been strapped to the sprinkler mains. (massive systems can have multiple -- and colossal -- pipes; such scale is rarely ever encountered) (Boeing super plant in Everett)

It's from this enclosure that a Greenfield whip is run to some adjacent wall -- typically.

What triple seems to be describing is a set up that has a common 4 square box nippled directly into the (Pott?) box that holds the micro-switches -- using a stubby GRC nipple and some lock-nuts.

Is that right triple?

&&&&&&

While not exactly at the flow switch, I've seen, and installed F/A circuit components in exactly such a manner -- and the AHJ was delighted.

For, there are tamper switches without limit in some schemes. And these tamper switches have SHORT LEADS that HAVE to be landed in a proximate junction box for make-up.

This is compounded by the fact that there is absolutely no way to mount such boxes without running up some insane design and engineering tab. The valves they monitor are clustered all over the critical pipes.

My AHJ was thrilled that I'd even linked them with free-flying EMT. Usually, these connections are made in Greenfield.

In every instance, no strapping is used.

&&&&&

Folks, we're describing controlled spaces that are only ever accessible to techs, electricians, and emergency responders and AHJ.

These spaces are NOT storage spaces, habitable spaces, ... etc. All alien gear is expelled.

There are no field reports of traumas to these schemes.

&&&&&&

Redundant fire bells are quite a 'tell' as they are common as dust when schools are expanded -- with additional sprinklers -- and additional 'sprinkler mains.'

The AHJ is going to insist that each riser get a fire bell. EVERY fireman is trained to expect a riser with each (classic) fire bell.

While the general public is under the impression that such bells are fire bells -- to a fireman they are merely markers for where they must run to TURN OFF THE SPIGOT.

[ Water Bells? ]

During such distress, there is NO TIME to even read big fat door legends such as "FIRE MAIN" "FIRE ROOM" etc.

{{{

Indeed, during such fiascos, the electric power is even at risk.

So the sprinkler boys even have bells that run on water flow itself! (Not so popular these days -- pricy -- and usually design restricted to REALLY hazardous applications.

( Some structures have power trip circuits that will kill all line voltage -- from the outset. This is typical of all high risk assets. (Lumber mills, chemical plants, ...))

}}}

I stopped worrying about big design issues when I was an apprentice. Every over-active electrician that attempted to help out/ get into design ended up being fired/ 'relocated' etc.

This included electricians up to and including a general foreman -- who was a genius, BTW.

It is TABOO to 'correct' the other guys' work.

In the worst possible situations, you'll end up being right. That's how the brilliant general electrical foreman got fired and -- driven out of the industry!

(Not to worry, he made his millions in the stock market and didn't need to work in the first place.)

&&&&

Lastly, offending craftwork is seen all the time.

In which case, take digital pictures and upload them to ECN. Then we all can sound off.

Pictures beat written descriptions of poor workmanship every time!


Edited by Tesla (03/11/15 08:21 AM)
_________________________
Tesla

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#215156 - 03/11/15 12:19 PM Re: wiring tamper switches [Re: triple]
HotLine1 Offline

Member

Registered: 04/03/02
Posts: 6785
Loc: Brick, NJ USA
triple:
Your scenario is best said as 'standard practice'.

What I usually encounter is either flex or EMT (occasional RGC) from the 4 sq to a structure wall and continued to a FA panel.

As Tesla said, there usually is no practical item to mechanically secure the box, other then onto the switch nipple.

IMHO, it is acceptable install.
_________________________
John

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#215158 - 03/11/15 12:28 PM Re: wiring tamper switches [Re: triple]
triple Offline
Member

Registered: 04/01/02
Posts: 182
Loc: Wisconsin
I know it is standard practice. That was my point. I and everyone I have ever worked with does it exactly that way. A hubbed box (Bell box, weatherproof box) would provide MUCH better support and take no additional work. I am surprised that that isn't the "standard practice".

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