Mounting Metal Halide fixtures

[dropd80s]

I just purchased some used Metal Halide pieces and am trying to figure out how to mount them. The ballasts have a flange on top that look like the one in the picture below. They will also be suspended from a vaulted cieling, not flat. Any ideas?

 

[Mike.ASC]

There should be a sheet metal box shaped bracket that bolts into the hole in your picture and the bracket should have the means to mount it depending on how you want to mount it . If the mounting brackets that I described are missing I would assume you could order them from the manufacturer of the lights or a electrical supplier .

Mike

 

[dropd80s]

Something like this, stolen from Charles (in GA), would work great. Any one know if this box attached to the flange is available, or something comparable? I need to get these up asap, while I still have my borrowed scissor lift available!

 

[Aceman]

I agree with what Mike said. You're missing the box on top to hold the wires. It'll usually have a threaded 3/4 hub on top.

Then you can buy a light hook seperately that'll screw into that and then hang it from an eyebolt or whatever in the ceiling.

 

[Charles (in GA)]

There is the box, and an endplate for the box, three screws in all. The box has a flange that goes under the flange on the ballast housing, and carries the weight. Screws are just to retain it. Mine came with the hooks, wire goes thru a hole in the middle of the hook and the splice is made inside the box. The box is necessary for a complete fire proof installation. My boxes were stamped formed steel, they may have switched to aluminum, they install the same. They are specified with the fixture since there are several different designs depending on the mounting method.

Pendant splice box threaded for 3/4" conduit (standard). Pendant splice box – removable cast-aluminum box slides on integral die-cast aluminum housing mounting flange and mounts to 3/4" pendant conduit prior to ballast housing installation. Matching wire access cover accepts RELOC® modular wiring. Complete assembly meets or exceeds UL 50-pound pull test. Other mounting options available.

Charles

 

[nehog]

...

Note: (and the above illustration shows this was not done) You must have safety chains or cables on hanging lights such as these. These safety chains must be attached to a secondary mounting, be of sufficient strength to hold the light should the primary mount fail.

 

[rkevins]

I agree, the top box with the hanger is missing, I spent the most of a day scrapping out a bunch of these lights in the plant where I work.

 

[Charles (in GA)]

Note: (and the above illustration shows this was not done) You must have safety chains or cables on hanging lights such as these. These safety chains must be attached to a secondary mounting, be of sufficient strength to hold the light should the primary mount fail.

I would be interested to see a code cite on this. A review of NEC Articles 410 and 314 don't reveal any such requirements that I could find. I looked in the Lithonia catalog and it lists a "Safety Chain Kit" as a field installable option. It apparently cannot be specified as part of the light fixture when ordering like many of the other options. I have looked at many of these light installations in the course of planning the install on mine, every time I walked into a Home Depot or Lowes, or anywhere where there were MH lights (or any pendant mounted lights) and I've never seen a safety chain on one. It may be a local or state requirement in some areas (such as California due to earthquakes), but I cannot find it in the code.

The method of attachment to the ballast housing (I have ballast housings like that in the illustration) requires screws joining the halves of the housing to be disturbed, which mine never have.

As a side note, my workplace installed a couple of thousand or more, 8 tube, T5HO fixtures using 36 inch downrods (conduit), and hooks on the end of the conduit, with the cord routed thru the conduit and hook, and none of these were attached with safety chains (I paid particular attention to the fixtures, hooks and pendants, as I was trying to figure out how to get a dozen or so of these out the door in my lunch box ) alas, they were 460v fixtures, with one of these replacing two 400 watt sodium fixtures which were mounted close together in pairs originally.

Charles

 

[Charles (in GA)]

Also, be aware that the wire or cord connected to these fixtures must be 105°C rated wire. I got lucky, and pulled a couple of hundred feet of 14 gauge yellow jacketed cord with the 105°C rating on it, out of the scrap bin at work. It was dirty and nasty, and had a couple of bad spots in it, but I soaked it in a bucket of Tide overnight (with the ends and bad areas hanging out of the water) and it wiped clean. The markings, though washed out, were still legible.

The temp requirement is due to the heat generated by the bulb and ballast.

Charles

 

[dropd80s]

My ballasts are tagged as requiring 90*C wire only, in which THHN should be sufficient, correct?

 

[Charles (in GA)]

My ballasts are tagged as requiring 90*C wire only, in which THHN should be sufficient, correct?

That is true. THHN is 90°C wire as far as I know. I'll have to look at mine again (I have one spare on the shelf), was thinking it called out 105°C wire, could be wrong, in any case, that is what I used for my plug and cord connection.

Charles

 

[dropd80s]

Here is the tag off the ballast with the 90*C wire spec.

I can see using a plug and cord in your instance, since you had the wire available. I plan on hardwiring to the splice box from my J box with Armored Cable. Any down side to doing it this way, other than not being able to easily remove the fixture? AC is available with 90*C rated wire correct?

Also I was planning on running six of these MHs at 120V on two seperate 15A circuits (three fixtures ea.) controled by two switches. Is there any problem with this? Would a branch circuit with a shared neutral and double pole breaker be a better option? I am planning on running #12 wire through out. If a branch circuit is a better option, would the neutral wire size need to be increased?

Thanks for all the help!

 

[Charles (in GA)]

At 120v these lights will draw exactly 4.0 amps. On a 15 amp lighting circuit, you are not allowed to exceed 12 amps, which is the 80% of circuit capacity max allowed by NEC for lighting and other continuous load items. You will be right at the limit, do NOT connect anything else to the circuit.

If you are running #12 wire, I'm not sure why you want to use a 15 amp breaker, you should be using a 20 amp breaker.

The "branch circuit" you are describing is technically known as a multi-wire circuit and sometimes also known as an Edison multi-wire circuit. There is no need or requirement to upsize the shared neutral on a multi-wire circuit.

You may wish to read up on multi-wire circuits before you start, it will take a fair amount of planning, and for best efficiency you will want a balanced circuit, having an equal number of lights on each side of the circuit, this reduces the load on the neutral to zero in places and in others, it is only the load of one or two lights, depending on how you wire it up.

I used three separate MW circuits each powering four lights, with double pole switches controlling each circuit.

Forgot, you've already seen my thread..........

Charles