The Electrical Contractor Network

ECN Electrical Forum
Discussion Forums for Electricians, Inspectors and Related Professionals

Books, Tools and Test Equipment for Electrical and Construction Trades

Register Now!

Register Now!

We want your input!

Featured:
   

2017 NEC and Related
2017 NEC
Now Available!

   
Recent Posts
breaker meltdown
by sparky
Yesterday at 07:30 PM
230 or 345 kV transmission lines?
by Vlado
09/24/16 09:33 AM
Electrical mast flashing product
by ThomasWinfrey
09/22/16 12:14 AM
What estimating software do you recommend?
by sparky
09/21/16 07:20 PM
"Dry Run" Inspection goes awry
by HotLine1
09/20/16 07:39 PM
New in the Gallery:
12.5A through 0.75mm˛ flex (just out of curiosity)
Shout Box

Top Posters (30 Days)
HotLine1 13
sparky 10
gfretwell 8
sparky66wv 8
Vlado 6
Who's Online
0 registered (), 258 Guests and 4 Spiders online.
Key: Admin, Global Mod, Mod
Topic Options
Rate This Topic
#213814 - 07/29/14 11:10 PM Current Limiter in track lighting
Potseal Offline
Member

Registered: 02/23/13
Posts: 187
Loc: 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

Top
2014 / 2011 NEC & Related Books and Study Guides
#213815 - 07/30/14 04:03 AM Re: Current Limiter in track lighting [Re: Potseal]
Tesla Offline
Member

Registered: 06/16/04
Posts: 1280
Loc: 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

Top
#213816 - 07/30/14 07:05 AM Re: Current Limiter in track lighting [Re: Potseal]
Potseal Offline
Member

Registered: 02/23/13
Posts: 187
Loc: 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

Top
#213817 - 07/30/14 04:09 PM Re: Current Limiter in track lighting [Re: Potseal]
Tesla Offline
Member

Registered: 06/16/04
Posts: 1280
Loc: 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

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

Member

Registered: 04/03/02
Posts: 6785
Loc: 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

Top
#213822 - 07/31/14 05:59 AM Re: Current Limiter in track lighting [Re: Potseal]
wire_twister Offline
Member

Registered: 07/25/07
Posts: 265
Loc: 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

Top
#213823 - 07/31/14 10:19 PM Re: Current Limiter in track lighting [Re: Potseal]
Tesla Offline
Member

Registered: 06/16/04
Posts: 1280
Loc: 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

Top
#213828 - 08/02/14 11:14 AM Re: Current Limiter in track lighting [Re: Potseal]
HotLine1 Offline

Member

Registered: 04/03/02
Posts: 6785
Loc: Brick, NJ USA
More like a 'clicks-on' thermo small motor OL, as opposed to a auto flasher??
_________________________
John

Top



ECN Electrical Forums - sponsored by Electrical Contractor Network - Electrical and Code Related Discussion for Electrical Contractors, Electricians, Inspectors, Instructors, Engineers and other related Professionals