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In-Wall light timers + CF lights

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GreySoul

Thu Jun 07 2007, 11:50PM

Registered Member #546 Joined: Fri Feb 23 2007, 11:43PM
Location: Albuquerque, NM
Posts: 239

So I recently purchased an Intermatic EJ500:

On several pages in the manual it warns against using this timer on CF lights, florescent starter ballasts, HID lights, televisions, appliances, and pretty much anything but old fashion incandescent light bulbs.

From what I can tell inside is basically a generic clock/timer chip and a solid state relay of some design...

So I hooked it up to my outdoor security lights and porch light, a mix of CF and PAR lamps... and hit the ON button and...

well....

it SEEMS to work just fine. Nothing gets warm, buzzes, sparks, smokes, or flickers.

<tinfoil hat>
So I'm wondering if they put that warning on there for any real reason, or is it some weird conspiracy by Intermatic against the CF industry?
</tinfoil hat>

-Doug

...

Fri Jun 08 2007, 01:32AM

Registered Member #56 Joined: Thu Feb 09 2006, 05:02AM
Location: Southern Califorina, USA
Posts: 2445

well, it is just a triac in there, which works great for a resistive load, but when you put a big fat transformer on it you run the risk of spikes and other nastiness, which the designers didn't want to worry about. So it is the kind of thing were it could work fine for the next 50 years, it could blow up the next time you turn it on.

GreySoul

Fri Jun 08 2007, 03:06AM

Registered Member #546 Joined: Fri Feb 23 2007, 11:43PM
Location: Albuquerque, NM
Posts: 239

By "blow up" would it be able to set the house on fire, or just kinda poof and stop working? Right now I have about 280 Watts on it. max would be about 900W if all bulbs were big flood lamps.

I can't recall ever seeing a triac fail, so I just don't know if they usually catch fire or just click off.

-Doug

...

Fri Jun 08 2007, 05:46AM

Registered Member #56 Joined: Thu Feb 09 2006, 05:02AM
Location: Southern Califorina, USA
Posts: 2445

Well, so long as the line is on a properly rated breaker it should just stop working. The chances of it drawing enough power to do any damage, and not blow a breaker is very slim.

Wolfram

Fri Jun 08 2007, 11:11AM

Registered Member #33 Joined: Sat Feb 04 2006, 01:31PM
Location: Norway
Posts: 971

Especially check out the scope shots farther down the page.

IamSmooth

Fri Jun 08 2007, 03:29PM

Registered Member #190 Joined: Fri Feb 17 2006, 12:00AM
Location:
Posts: 1567

As a homeowner I would personally avoid violating building codes and electrical warnings. If a fire did occur it would void your homeowner's insurance.

Dr. Shark

Fri Jun 08 2007, 06:30PM

Registered Member #75 Joined: Thu Feb 09 2006, 09:30AM
Location: Montana, USA
Posts: 711

True, but so unlikely that I would take the gamble. Silicon fails either short or open, I have yet to see a single semiconductor that fails in some kind of medium impedance state that causes enough resistive heating to start a fire.

IamSmooth

Fri Jun 08 2007, 07:08PM

Registered Member #190 Joined: Fri Feb 17 2006, 12:00AM
Location:
Posts: 1567

I guess, Joe. Just make sure the fuse is rated properly for the household wire.

Carbon_Rod

Fri Jun 08 2007, 07:15PM

Registered Member #65 Joined: Thu Feb 09 2006, 06:43AM
Location:
Posts: 1155

Most systems like this use AC phase choppers...

You can actually dim a CF slightly without too much damage to the starter electronics. However, the CF efficiency degrades very quickly and will sometimes setup a flickering oscillation.

Depending on how they keyed the zero crossing detection it could cause "brown out" like conditions and other problems. Hence, if one disables the dimmer feature it makes the 0.7 vAC roll off neglagable.

GreySoul

Fri Jun 08 2007, 11:17PM

Registered Member #546 Joined: Fri Feb 23 2007, 11:43PM
Location: Albuquerque, NM
Posts: 239

I am using a triac controlled TIMER not a DIMMER. My understanding of the triac in the full on position hardly touches the wave form... hence my lack of concern.

As for the way CFLs fail, yes I have seen that many times. I've been using CFLs since before they were commonly available and it's only recently that I've seen warning on TRIAC controlled devices. I have seen some pretty spectacular failures of CFLs, but they were all on normal circuits with no triac in between them and the house current - so I don't think it's the TRIAC that causes such failure.

If all it does it decrease the life span of the unit 10-15% I can live with that.

For now the experiment continues. I've got 2 CFLs and 2 PAR lamps on it. We'll see which blow up first. Ultimately I think the entire system could catch fire and it would be contained to the block wall and conduit - i just hope it doesn't come to that.

If I get anything other than an uneventful failure I'll let ya know

-Doug

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