Lots of puck lights

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jjhoward

jjhoward

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Northern NJ
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Owner TJ Electric
Got a new kitchen to do that has 24 puck lights.
12 on the bottom of the cabinets shinning down on the counter space, 12 on the top shelf of cabinets illuminating the shelf space behind glass doors.
The only xfomers I have installed are 60 watt max (3 lights).

Has anyone ever installed a larger xfomer to eliminate the multiple smaller ones? Then the snap switches would be used to switch the low voltage. Thank you for you suggestions.
 
Re: Lots of puck lights

Puck lights installed with the wiring open or visible. Must use a class II transformer rated at not more than 100 VA
TRUE - and not more than 5 amperes
Transformers with a VA rating of 101 to 1000 VA are class I. Class I wiring is required to be in conduit & Boxes. The secondary circuit must be protected not to exceed 25 amps.
Click to expand...
Joe, this quote is from another post at this forum that is on the same subject. The author is Pierre Belarge. You can go to the bank with his input.
 
Re: Lots of puck lights

I would never go with this many "puck" lights! Go look at SeaGull Lighting "Ambiance" system...it's a track with a Malibu-like cable in it, lampholders of 5-10w snap on to the track anywhere you want. Also, it uses 24v, so less voltage drop, etc. Feed it with #10 Romex or MC froma remote transformer, and use the small JBox to splice at the beginning of each run. 500W max per feed on this particular system (@24V)

Check out http://www.seagulllighting.com/Low-Voltage-Linear-Lighting.htm

for more info on this setup.

Mike
 
Re: Lots of puck lights

Macmikeman
I am honored that you said that, but I cannot take credit for all of that post. I was responding to an earlier post by someone else and part of the post you have shown is mostly his.

I will say this about all of those pucks lights though. There is new permission in 411.4 that permits the use of other than Chapter 3 wiring methods through framing methods. But it is very restrictive, as one will need to reference table 11(A). In short, the source will be limited in it's output level - with 24 pucks, you will need to use more sources, such as the Class 2 transformers. Contacting the manufacturer may help.

For those who may be wondering why "low voltage" lighting needs such strict rules, here is something to think about.

Fire needs 3 things
1. fuel
2. heat (energy)
3. oxygen

120 volt X 1 amp = 120VA (watts) - very similar to a 100 watt lamp.

12 volt X 10 = 120 VA HMMMMMM!!! Sounds like miswiring could lead to potential fires.
 
Re: Lots of puck lights

Thank you all for the info.
Mike, I like the looks of the linea lighting from Seagull.
Are you suggesting to provide power to the xformer with #10 Romex, isn't #12 OK?
Then us MC cable from the xformer to the various cabinets? At the cabinets splice onto the Seagull cable?

I am not sure about switching the voltage from the secondary of the xformer. Is that acceptable?
 
Re: Lots of puck lights

You are going to feed the lights with #10. You can use any size, but the secondary feed must be fused at the rating of the wire or less. Voltage drop becomes an issue, so I always use #10 unless it's a small run.

Remember, as voltage drops (120--->12/24v) our current (amps) must go up to supply the same wattage. So, at 24V, #10 will supply 600W (due to a 25A limitation on LV lighting ciruits). At 120, this same 25A will supply 3000W. However, the wire is just as loaded with the low voltage setup. This is why it can start fires just as well as 120. Since you are going through a wall, you have to use a Ch 3 wiring method (MC, Romex, EMT, etc). Then, the splices where the Ch 3 method comes out of the wall, use one of seagull's small splice boxes (9481-12) to transition to the seagull cable, which must be run on the surface, never concealed. If you run it through cabinet sides, you must sleeve it.

I wouldn't switch on the secondary...typically, I install a dimmer (LV Magnetic Type) to feed the primary of the transformer. Otherwise, you would always be energizing the primary and wasting energy, and heating the core. Seagull makes some small door switches for the secondary, but I'd use them in conjunction with a dimmer on the transformer. ie: walk in and turn on dimmer- undercabinet lighting turns on. Open a cabinet, and its individual light will turn on.

mike
 
Re: Lots of puck lights

I see fusable plugs from Seagull. Also, there is a note in there data sheets that states you should fuse the lv line if you exceed 60W at 12V or 100W @ 24v.

Is there some NEC reference that addresses this?

How do you fuse that secondary line if you snapping on fixtures to their cable? I see the fusable plugs for the puck lights. Is there an in line fuse for their cable?
 
Re: Lots of puck lights

From where it leaves the secondary of the transformer, the cable MUST be fused/circuit breakered at the capacity of the secondary wiring! Many transformers have this built in. If you try to use a buck/boost unit as some do, you would have to provide inline fuseholders inside the transformer. I use units from this company and it's all taken care of: http://www.q-tran.com/ That website has a lot of FAQ's about LV lighting, it is a good read if you do a lot of systems like this.

Those fuseholders that seagull sells are to make a Class 2 tap off of the main (class 1) LV line. You could run the whole system as Class 2, but you are very limited by wattage/amperage. (100W max, 5A max, I believe). I always build my systems to be Class 1 /Chapter 3 compliant, because it is easy and lets me use larger transformers and less home runs. Also, a little extra capacity, and less VD never hurt.

Remember, you have a 25A secondary limitation no matter what (Art 411). That's 600W at 24v, and 300W at 12V. Seagull limits the wattage on their cable to 500W at 24V. Plan accordingly.

mike
 
Re: Lots of puck lights

By Mike: If you try to use a buck/boost unit as some do, you would have to provide inline fuseholders inside the transformer.
Click to expand...
Mike Read 411.3, Listed system. No LV lights I have ever seen come with a buck/boost transformer as part of a listed system?
 
Re: Lots of puck lights

Wayne,
I don't use Buck/Boost units, as it is a code violation. Unfortuantely, they are pushed by a lot of supply houses when a contractor asks for a LV lighting transformer. I have even seen some sold by LV lighting manufacturers (usually the Malibu type of companies) that have a primary CB, but nothing on the secondary!

If you want to be compliant, be sure the transformer has primary and secondary protection. Units from QTran, and SemperFi (http://www.semperfipowersupply.com/) will give you the eaiest install that I know of, and they are UL lissted for the purpose.

Also, treat the secondary wiring the same as 120V, and you will be OK!

mike
 
Re: Lots of puck lights

I have always thought that a "lighting system" Would include the fixtures also as a compleat set, after reading 411.2 It sounds like it's just the power supply? :confused:

And 411.3 say "shall be listed for the purpose" which any LV fixture would be for that purpose? :confused:

So why did they state "lighting system" when "power supply" would made much more sense?
 
Re: Lots of puck lights

Its rare to see a "complete set" of lighting fixtures, cables and transformers. And even then, it's usually customizable. I agree, the "complete system" is misleading and inacurate. I don't even know if UL has a category for a whole system. I know there is one for the power supply, but most of the fixtures I have used are listed by ETL or one of the other labs. Some of these are top notch fixtures (see BK Lighting).

In my opinion, Art 411 leaves a lot to be desired, and really passes the buck to the listing agencies! OTOH I'm not up to rewriting it!

mike

[ November 08, 2005, 12:24 PM: Message edited by: mhulbert ]
 
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