Charcoalized wood. How hazardous is it?

[ike5547]

I ran into this while taking down a halogen fixture but I'm having a hard time finding precise info as to its degree of danger. The customer wants to keep the fixture. Am I making too big a deal out of this?

 

[LarryFine]

480 needs to see this picture. He's asking about using a single 100w bulb in a fixture rated for two 60's.

 

[Pierre C Belarge]

This can be potentially dangerous. The carbonized wood is one step away from combustion. It is just a matter of time. You need to find out what is creating this situation.

 

[ike5547]

That picture doesn't do justice as to how dry that wood seems to be when you're standing in front of it.

 

[ike5547]

This can be potentially dangerous. The carbonized wood is one step away from combustion. It is just a matter of time. You need to find out what is creating this situation.

Re: Carbonized wood

Thanks. Carbonized wood is yielding results on google. "Charcoalized" wood was drawing a blank.

PS) The situation seems to be the halogen lamps.

 

[buldogg]

I ran into this while taking down a halogen fixture but I'm having a hard time finding precise info as to its degree of danger. The customer wants to keep the fixture. Am I making too big a deal out of this?

Tell your customer he can keep the fixture, just not put back in that location.

 

[hurk27]

Tell your customer he can keep the fixture, just not put back in that location.

Or at least use one of those ceramic medallions to go between the wood and the fixture?

 

[SG-1]

You may want to search pyrophoric carbonization, for some interesting reading to share with the customer. IMO he needs to get rid of the fixture, before it takes down the house.

 

[SG-1]

Or at least use one of those ceramic medallions to go between the wood and the fixture?

Sand off the carbon first ?
That way you find out how deep it is.

 

[e57]

It may be that this fool would like to keep the fixture - but it may need to be explained to him that the measurement of wattage is actually a measurement of heat in it's longest end form... (much like BTU's in a much shorter form) The fixture may have been defective, by design, or modification (like removing that bulky foil covered insulation it may have had) - but the bottom line is it is a hazard to have it installed on a combustible material - IF THAT IS ACTUALLY HEAT DAMAGE?

However that is a wood surface that has been stained - and it will fade lighter when exposed to light/UV - are you sure it was not stained that color originally? Then all the rest of the room got exposed to either light from the sun, and the fixture itself - but not where the fixture was covering the wood.... And certain stains will also darken when exposed to heat...

The man in the comfy chair says - you make the call....

 

[ptonsparky]

What is/were the condition of the conductors? They should have been discolored and quite brittle if this was a heat problem.

Oftened wondered why we have to be so careful about gaps at the box edge then allow fixture wires to fly everywhere under a canopy.

 

[M. D.]

I'm gonna go out on a limb and say that the branch circuit wiring is not rated for the connection of this fixture ,.. looks old to me my guess the fixture came with a warning... I would not want to re install it regardless.

U.L. marking guide for luminaires

SUPPLY WIRE TEMPERATURE ? luminaires that require greater than 60 ?C supply wire are
marked ?MIN ___ ?C SUPPLY CONDUCTORS? for which blank space is replaced with the
temperature.
Luminaires intended to be installed in a dwelling, connected to or over an outlet box, and
marked for supply wire rated 75?C or 90?C are additionally marked on the luminaire and on the
carton ?CAUTION - RISK OF FIRE. CONSULT A QUALIFIED ELECTRICIAN TO ENSURE
CORRECT BRANCH CIRCUIT CONDUCTOR,? or just the carton may be marked ?CAUTION ?
RISK OF FIRE. THIS PRODUCT MUST BE INSTALLED IN ACCORDANCE WITH THE
APPLICABLE INSTALLATION CODE BY A PERSON FAMILIAR WITH THE CONSTRUCTION
AND OPERATION OF THE PRODUCT AND THE HAZARDS INVOVLED.?

It might have been marked as :

NON-COMBUSTIBLE SURFACE ONLY ? A ceiling mounted or ground-mounted recess
luminaire that is permitted to be mounted only to a noncombustible ceiling because of
temperature or other considerations is marked ?NONCOMBUSTIBLE SURFACE ONLY.?

 

[ike5547]

However that is a wood surface that has been stained - and it will fade lighter when exposed to light/UV - are you sure it was not stained that color originally? Then all the rest of the room got exposed to either light from the sun, and the fixture itself - but not where the fixture was covering the wood.... And certain stains will also darken when exposed to heat...

It's the dark little room across the way in the photo. If you were to drag a finger nail across the wood under the fixture you would get soot stuck under the nail.

 

[Pierre C Belarge]

Adding section numbers to the post from MD

410.21 Temperature Limit of Conductors in Outlet Boxes.

410.23 Covering of Combustible Material at Outlet Boxes.


I would also check the effective ground fault current path of this installation.

 

[Jim W in Tampa]

They can keep the fixture untill the day of the fire. Protect yourself here. I would not risk being involved in reinstalling. Note it on your bill and take photo. They can find a handy man to install. In time i think it will burn. Some customers simply do not care to listen. You warned them and thats about as far as you can take it.

 

[Power Tech]

Talk them into a fluorescent.

if you put another incandescent in there you will be at square one.

The correct term is "pyrolysis", which happens with wood at 300 C.

 

[weressl]

Or at least use one of those ceramic medallions to go between the wood and the fixture?

Used to be made of plaster, but I think it is made of styrofoam nowadays. Otherwise it is a good idea

 

[LarryFine]

Used to be made of plaster, but I think it is made of styrofoam nowadays.

Actually, I believe most of them are made of polyurethane now.

 

[hurk27]

Actually, I believe most of them are made of polyurethane now.

We can still get the plaster/ceramic ones, one lighting outlet here has them.

I was thinking also , with this fixture, I know bi-pin T-3 quartz lamps will fit wattages from 50 to 250 watts, I wonder what was found in the fixture?, and what it was rated for?

Any photo's of the fixture?

 

[ike5547]

Any photo's of the fixture?

Nope. I won't be back there again until next week. There're three 50W MR16s in it now. The fixture is probably custom made --unlisted, etc., etc-- There are three small electronic transformers above the canopy; there wasn't one of those little fiberglass heat barrier/shield thingies above the canopy when I took it down.

It's made all of brass and actually looks pretty good.

The customer is going to let me install some of those MR16 LED lamps in place of the halogen. Do they dim, do you think? He's got these 'custom' dimmers installed everywhere and probably doesn't want to lose one of those either.