I am building a MH table lamp. I have a couple of questions, so here I go.

1. Is it OK to use standard lamp wire between ballast and lamp holder ? The ignitor is in the ballast compartment and the pulse rated lamp holder is by itself so this wire endures the pulse. There is about 18-24" of wire between ballast box and lamp holder. I'd use something else, but I am not sure what, where to buy it and it has to be small enough to go through the lamp threaded tube. The standard lamp wire works, but in the long term, I'm not sure. What worries me the most is should the lamp be lit and the power flickers enough to extinguish. During the restrike time, I wouldn't want to have a flashover.

2. Is it OK to use standard wire nuts to connect the lamp holder (it also has to withstand the pulse).

The project is almost finished. There's a bit more work to do, but when it is finished, I'll follow up with pictures.

If you can find it, I suggest 250c rated fiberglass TGGT wires and a ceramic lampholder. I've used standard blue wirenut a for that kind of thing and it works out fine.

COOL!!!Make your own "Microsun" desk light!

Aside from the temperature rating, is there harm in using lamp cord for ballast-to-lampholder wiring ? The lamp holder is pulse rated porcelain.

Idk, I used a remote 100w HPS setup for a lamp but MH may be different due to higher ocv of the ballest.

There are two levels of the problem:
Legally the setup won't be code compliant (the fixture is not certified - and I guess it will fail to contain the remains of an exploded unprotected MH, yet not prevent it's use). With all legal consequences (mainly if used in a professional manner, maybe insurance coverage,... - this you have to check yourself).

Technically to get the setup reasonably safe:
You may start with an assumption of if the European wiring materials are safe for 240V include the ignition pulses, it should not make any other problems anywhere else, if the voltages are the same (and the 220..240V OCV of the pulse MH ballast is the same range as European mains)
So if you get a 3x0.75mm^2 cable with double insulation (just a "reinforced" insulation is not sufficient for power cords), it should be safe.

Definitely the fixture itself should be grounded, all the pulse rated sockets count on the metal work around to be grounded, so an eventual breakdown to it won't become a direct safety hazard.

And of course make sure you use only protected lamps (European codes require to mark the socket accordingly with all the limitations for the used lamp - so "xxxW protected MH only" or so)

I think in due course I will get high temp fibreglass braided wire. The lamp holder is porcelain pulse rated, and I have no intention of using lamps other than protected (for obvious reasons). The fixture has a grounded mains cord so it should be good for that part.

As for certification, any home made fixture lacks such certificate. Since this lamp is intended for home use, it shouldn't be a problem. I know accidents happen, but this lamp is not intended to be used when no one is home.

I assume commercially available PSMH fixtures use TGGT glass reinforced wire to the lamp holder. That is what appears to be affixed to my lamp holder.

I might make a label to use only protected lamps, too.

Yes, i got two medium sockets by leviton that are TGGT wired. I think mogul sockets with built in wires have something like 450c since the fiberglass and silicone insulation is thicker than regular TGGT I see.

And you can't have the wire too thin and long, Or the voltage drop will make it useless.

The wire length is about 24 inches and the gauge is 18 AWG. I will get some TGGT wire in due course. The actual wire is 18 AWG lamp cord and the lamp has no problem starting. The insulation is not sufficient for long term use, though.

The wire length is about 24 inches and the gauge is 18 AWG. I will get some TGGT wire in due course. The actual wire is 18 AWG lamp cord and the lamp has no problem starting. The insulation is not sufficient for long term use, though.

Why is it not sufficient for long term use? Does it get hot? There are air cooling and water cooling options available.

Quote from: sol on February 26, 2016, 03:31:02 PM

The wire length is about 24 inches and the gauge is 18 AWG. I will get some TGGT wire in due course. The actual wire is 18 AWG lamp cord and the lamp has no problem starting. The insulation is not sufficient for long term use, though.

Why is it not sufficient for long term use? Does it get hot? There are air cooling and water cooling options available.

The problem is not with the core thickness, the currents are rather small, so make practically no heat at all.
The question is, whether the insulation of a standard table lamp cord may handle the ignition peak voltage.
The insulation does not have to break immediately at the first time the excessive voltage is present (e.g. 4klV pulse on just 120V rated cord), but when certain limit is exceeded, the structure gradually changes and so builds up the damage (traps) over time and so breaks after some longer time.
And for that the cooling or so does not help at all (although elevated temperature tend to accelerate the process quite a lot).

The problem is not with the core thickness, the currents are rather small, so make practically no heat at all.
The question is, whether the insulation of a standard table lamp cord may handle the ignition peak voltage.
The insulation does not have to break immediately at the first time the excessive voltage is present (e.g. 4klV pulse on just 120V rated cord), but when certain limit is exceeded, the structure gradually changes and so builds up the damage (traps) over time and so breaks after some longer time.
And for that the cooling or so does not help at all (although elevated temperature tend to accelerate the process quite a lot).

This is exactly the reason why I am going to replace it with TGGT wire. For now, it suffices, but for long term use (which is what I want to do) the special insulation is better. I don't anticipate making hot restrikes often, but it is an eventuality that will surely happen sometimes. Better safe than sorry.

While on the topic of the wires, since the new wires will be two individual wires (not stuck together like lamp cord), would it be better to slightly twist them together or leave them both in a straight line in the lamp column ? I imagine a slight twist would cancel out unwanted interference with the ignition pulse, or maybe unwanted interference with other electronic appliances (radios, etc).

Quote from: Medved on February 27, 2016, 04:01:29 PM

The problem is not with the core thickness, the currents are rather small, so make practically no heat at all.
The question is, whether the insulation of a standard table lamp cord may handle the ignition peak voltage.
The insulation does not have to break immediately at the first time the excessive voltage is present (e.g. 4klV pulse on just 120V rated cord), but when certain limit is exceeded, the structure gradually changes and so builds up the damage (traps) over time and so breaks after some longer time.
And for that the cooling or so does not help at all (although elevated temperature tend to accelerate the process quite a lot).

This is exactly the reason why I am going to replace it with TGGT wire. For now, it suffices, but for long term use (which is what I want to do) the special insulation is better. I don't anticipate making hot restrikes often, but it is an eventuality that will surely happen sometimes. Better safe than sorry.

While on the topic of the wires, since the new wires will be two individual wires (not stuck together like lamp cord), would it be better to slightly twist them together or leave them both in a straight line in the lamp column ? I imagine a slight twist would cancel out unwanted interference with the ignition pulse, or maybe unwanted interference with other electronic appliances (radios, etc).

Or what about ferrite core wire noise filtering?

Yes, didn't think of that one. I will, however, wait until it is complete to see if there is any interference with any other machine in the house before adding something to reduce it.

Regarding a ballast, I have a magnetic ballast in there at the moment. Unfortunately, I misplaced the mounting hardware so it is loose in the bottom of the junction box for now. The vibration is such that it is VERY noisy, something that could probably be cured with proper mounting. I used it twice, and the flicker is noticeable and could get annoying. I am somewhat sensitive to flicker (the flicker from fluorescents on magnetic ballasts don't bother me, however, only on HID and LED). Because of those two factors, I am waiting for an electronic ballast from eBay (Universal). It should quiet it down and stop the noticeable flicker. I imagine that an electronic ballast could make some interference that would inhibit FM reception, but I'll wait and see before making corrective actions.

There are stores around here that have changed to electronic T8 (some years ago, some recently) and others have changed to LED. I have noticed that when I am listening to FM radio in the car and I go by those stores, the reception is problematic. It didn't happen when those stores were magnetic. However, we're talking about lots (100's) of ballasts in the stores compared to one lowly 50W MH ballast in my house. I'll keep you posted.