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#213814 - 07/30/14 02:10 AM Current Limiter in track lighting  
Potseal  Offline
Member
Joined: Feb 2013
Posts: 236
Saskatchewan
I'm currently involved in the install of a Starbucks. Not much work involved since it's a modular set-up with a lot of "plug and play". After looking over the drawings I noticed that there is a "current limiter" for the track lighting. Never seen this before and decided to research what purpose it serves. Found a lot of US information regarding energy conservation and it makes sense from that point of view when taking into consideration the building codes in certain US states (especially California). Therefore, since this is a US company the current limiter is simply a design feature that really serves no BENEFIT here in Canada - is that a correct assumption?


A malfunction at the junction

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#213815 - 07/30/14 07:03 AM Re: Current Limiter in track lighting [Re: Potseal]  
Tesla  Offline
Member
Joined: Jun 2004
Posts: 1,273
Sacramento, CA
Not so fast. Track lighting is vulnerable to over lamping.

The design you've described throttles the juice without popping the breaker.

HQ (Starbucks) realizes that they can't stop the field troops from over lamping this or that specific track within their track lighting.

Thus, the design saves the track rails and stops the lamps from cooking the over all backbone.

This vulnerablity is pretty much unique to track lighting and other rail based systems.

The protection was probably throw in only after melt downs in other locations. (You can't cure stupid.)

And, obviously, having the lamps cut out during the work day would be a sales downer.

The last Starbucks I saw (inside a Safeway) had a sub-panel right out there on the floor. It was ordinarily kept under lock and key. So you can imagine the practical troubles if the breakers tripped and the boss man was not there with the key.


Tesla

#213816 - 07/30/14 10:05 AM Re: Current Limiter in track lighting [Re: Potseal]  
Potseal  Offline
Member
Joined: Feb 2013
Posts: 236
Saskatchewan
Thanks for the reply Tesla. That's the information I thought I was going to find. Instead all roads led to energy conservation. Your explanation makes a lot of sense. Nonetheless, here's a sample of what I was finding online concerning track lighting with current limiters:

http://www.lightingservicesinc.com/files/pdf/Track_Current_Limiter_07_08.pdf


A malfunction at the junction

#213817 - 07/30/14 07:09 PM Re: Current Limiter in track lighting [Re: Potseal]  
Tesla  Offline
Member
Joined: Jun 2004
Posts: 1,273
Sacramento, CA
That's interesting.

In my professional experience I've found that the track rails/ conductors were positively glowing under load.

And they were totally exposed to the air!

When de-energized, they were WAY too hot to touch.

You could smell them cooking the plastic. And this was a 277VAC set up. (The fixture was labeled for 277VAC, too.)

Paralleling resistors causes their net resistance to drop. When the track rail is powering up purely resistive lighting loads, this axiom applies.

Consequently, ever more current rushes into the hot rail.

The general public just figures that they can lay in as many track fixtures as they might want... no problem!

That would be no different than a j-man stringing up an absurd number of fixtures on a common lighting circuit.

It's just that track lighting lends itself to such abuse.


Tesla

#213818 - 07/30/14 10:07 PM Re: Current Limiter in track lighting [Re: Potseal]  
HotLine1  Offline


Member
Joined: Apr 2002
Posts: 6,858
Brick, NJ USA
Tesla:
A regular service call for anational chain was 'track problems'

It was always burn outs from the store guys either relamping with the wrong bulbs, or moving heads.

The burn outs were couplings and track, or feed end and track. By the grace of someone, there were no actual fires.

As the service calls & materials dented the corporate pocketbooks, the solution back then was switching the PAR headsout to LV MR-16 with the only bulbs being available being 20 watts. The current limiters would have been good back then.

BTW, the track was comm grade HALO, single and two circ.


John

#213822 - 07/31/14 08:59 AM Re: Current Limiter in track lighting [Re: Potseal]  
wire_twister  Offline
Member
Joined: Jul 2007
Posts: 265
Georgia USA
The current limiter is in ceiling fan light kits as well. It turns the lights off if the wattage is too high, of course it must heat up before they go off, then when it cools they come back on. I have had multiple service calls for these things failing even with the correct or lower wattage bulbs in them, just another piece of technology rushed to market and forced on the people in the name of something, when its only real purpose is to make money for the manufacturer.


Jimmy

Life is tough, Life is tougher when you are stupid

#213823 - 08/01/14 01:19 AM Re: Current Limiter in track lighting [Re: Potseal]  
Tesla  Offline
Member
Joined: Jun 2004
Posts: 1,273
Sacramento, CA
wire twister...

Are you describing a slow motion version of an automobile flasher....

As the dynamic you've laid out is apparently thermo-resistive.

In which case, it's a 'tuned' circuit that's destined to create headaches.




Tesla

#213828 - 08/02/14 02:14 PM Re: Current Limiter in track lighting [Re: Potseal]  
HotLine1  Offline


Member
Joined: Apr 2002
Posts: 6,858
Brick, NJ USA
More like a 'clicks-on' thermo small motor OL, as opposed to a auto flasher??



John


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