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💬General Category => General Discussion => Topic started by: rperego on December 15, 2009, 09:29:19 PM

Title: Lamp Module Melt down
Post by: rperego on December 15, 2009, 09:29:19 PM
Anyone ever had this happen?

This module melted to the point you can see in the picture, as well as melting the end of the cord it was plugged into, before tripping the breaker.

Granted, it was outside, but in a plastic baggie as I've been doing for over 20 years without incident.  During the holiday season where modules need to be on the end of extension cords, I secure them in plastic baggies, with the zip lock positioned down, and have never had a problem with water getting in them.  I'm pretty sure water didn't get in this one that burned up.

This was pretty scary considering how hot it must have been before tripping the breaker.
Title: Re: Lamp Module Melt down
Post by: Dan Lawrence on December 15, 2009, 10:16:14 PM
The only way you can burn out a module like that, it had to be overloaded for quite a while.   I've been using lamp modules since the 1980's and never had that happen.  I would never use a Lamp Module for an outside job, Appliance modules are better suited for loads like yours.
Title: Re: Lamp Module Melt down
Post by: rperego on December 15, 2009, 11:48:18 PM
The module was only powering a short string of mini lights, way under the rating of a lamp module.  However, perhaps the string of lights shorted out and hence bumped up the load.  Regardless, it seems strange that a unit would fry itself like this instead of merely failing in a less dangerous way. 
Title: Re: Lamp Module Melt down
Post by: Brian H on December 16, 2009, 06:18:55 AM
Sorry to read of the problem, but I am glad it was not worse than it was.

Thank you for sharing your experience. It maybe a warning to others to be carefull.

So the LM465 was on the end of an extension cord. Outside in a plastic bag that could have let moisture in.
Was the outlet it was in protected by a GFI device?
The normal current the module is designed for is about 2.5 amps for 300 watts.
A severe overload would burn it easily and the breaker being a 15 or 20 amp device through an extension cord may take a while to trip.

I did a destructive test on a Smarthome LampLinc. It has a fuse in the output that I bypassed and used a 1200 watt load on it. Boom flames and toxic smelling smoke.  rofl
Was outside for obvious reasons.  ;D
Title: Re: Lamp Module Melt down
Post by: HA Dave on December 16, 2009, 09:30:06 AM
So the LM465 was on the end of an extension cord. ..........
.....The normal current the module is designed for is about 2.5 amps for 300 watts.

Gee.. I was thinking (AND typing... never a good idea). If I was to use a lamp module to control a string of C7 lights... with each (C sized) bulb using 7 watts (hence the name C7). One string of 100 lights would use... 700 watts.. or (more than) twice the rated limit (for a lamp module). Of course... I wouldn't expect a 700 watt LOAD to trip a breaker (AKA: blow a fuse). Generally speaking it would take a short to blow the fuse.

So what does the one size down bulbs use in wattage? I don't mean the C5's... I mean the little skinny ones. I was thinking (risky post here) that a string of 100 of the little skinny ones use 250/350 watts.. which is it.

How does someone safely use X10 to control Christmas lights?
Title: Re: Lamp Module Melt down
Post by: Brian H on December 16, 2009, 10:36:03 AM
Maybe that is why the OEM B&D FWLR Lamp Module; from X10. Has a fuse on the output.
Title: Re: Lamp Module Melt down
Post by: Mel99 on December 16, 2009, 11:31:50 AM
I have 3 LM's controlling two types the little Christmas lights indoors.  One type draws .44 amp per string and the other draws .33 amp per string.  One LM has 3 strings of the .44 amp type the other two have one string each of the .33 amp.  They are all slaved off of an RR505 transceiver and I use a CR12A remote.  The only problem I experienced was that when I had all 4 devices set to different codes and tried to schedule their operation via a CM11A, it was intermittent.  So, I switched to the remote option.  I am now in the process of mapping all of my circuits and locating noise sources.
Title: Re: Lamp Module Melt down
Post by: Brian H on December 16, 2009, 11:47:09 AM
In an on line vendors sales pages.
I found C7 and C9 strings using 5 watt per bulb.
The miniature lights [Not LED] where between 125 ma 15 watts and 150 ma 18 watts.
LEDs where like 4.8 watts
Also most of the newer ones had fuses in their plugs. Not to say it could have been a short before the fuses.
Title: Re: Lamp Module Melt down
Post by: rperego on December 16, 2009, 07:49:38 PM
The fault may not have been with the lamp module.  Closer inspection of the end of the extension cord the lamp module was plugged into revealed that the lamp module input prongs had melted right off - the ends are still sticking in the socket.  This was a cord I should have abandoned long ago - the sockets (3 of them) on the female end had lost their tension and were quite corroded.  I think now what happened is the connection was bad and the prongs began arcing hence causing a lot of heat and the consequent burning of the X10 unit. 

This diagnosis also fits with what happened when I originally reset the breaker, before I discovered the cause.  When I reset the breaker there was intermittent buzzing in addition to the lights flickering in the room the panel is located.  The arcing was probably not constant, hence the spikes when the problem was happening likely were of short enough duration so the breaker didn't blow for some time - like enough time for the parts involved to starting melting down.

I also verified that the load on the module was only 25 watts (standard 50 bulb string of mini lights) and subsequent use shows it wasn't shorted out (it was also fused in the plug).

So, even though I'm concluding the problem was on the input side of the module, I'm going to make sure any more modules I buy are fused just in case a load is too high, especially after hearing that Brian forced one to catch fire from too high a load.  I'm not sure a GFI would have shut the line down any sooner in the situation I had, but I generally don't use them any way where wires are in wet conditions and I'm not running a tool etc. - they just trigger when you don't want them to.

Thanks for the input, Bob   
Title: Re: Lamp Module Melt down
Post by: dave w on December 16, 2009, 08:25:42 PM
Excellent diagnostics.
Title: Re: Lamp Module Melt down
Post by: Dan Lawrence on December 16, 2009, 10:01:58 PM
I would strongly suggest using only Appliance Modules for outside (Holiday) lighting, not Lamp Modules.  If the lights controlled are never dimmed, never use a Lamp Module.
Title: Re: Lamp Module Melt down
Post by: Brian H on December 17, 2009, 05:59:38 AM
Thank you for the updated information.

None of the X10 modules have fuses in them as far as I can tell. The OEM for B&D did, but they are discontinued and hard to find these days.

The module I forced to fail was a Smarthome Insteon LampLinc and I had to bypass the fuse to do it.
Title: Re: Lamp Module Melt down
Post by: gator.bigfoot on December 20, 2009, 12:45:05 PM
I have tried to use the PAM02 modules to control my Christmas lights.  The first one I tried went on but no longer goes off.  The second one I tried I reduced the load by 1/3 and it still did the same thing.  The second one eventually started to work again, but now I am afraid to try it again.  Currently they are controlled by some cheap household timers that work fine, but don't give me the control that I am looking for. Not sure what to try next.  The current lights are plugged into a normal household outlet rated at 15 amps.  My breaker system is Square D so going over the 80% limit is unlikely with their design. They always trip at anything above the 80% of FLC.  Perhaps the inrush cannot be handled by the module.  It is rated at 15amps, but no inrush rating given.   Perhaps I need to interface a contactor like I used for the pool pump?  That way it can handle the inrush and abuse.  Just don't want to go through the extra expense.
Title: Re: Lamp Module Melt down
Post by: Brian H on December 20, 2009, 01:09:10 PM
The PAM02 is rated as following and maybe on the back of the unit.
15 Amps Pure Resistive
1/3 Hp.
500 watt Incadescent Lights. I believe that takes the power on surge of cold bulbs into account.
400 Watts for a TV or Stereo type device.

How old are the modules?

They could be in a poor signal location.
Have you tried them in other locations?

What type of lights are they?

Title: Re: Lamp Module Melt down
Post by: gator.bigfoot on December 21, 2009, 03:41:26 PM
The PAM02 modules were brand new.  Never before used (other than testing a 100W light).  The Christmas lights are a combination of LED and In candescant lights.  I haven't done any load calculations to see if I exceeded the 500 watts incandescent lighting.  They are the old 7Watt ones so means around 70 pcs.  I didn't think I exceeded that limit, but like I said I didn't count them.  Not much point in saying a module is good for 15 amps and then limiting it to 500 watts. That's only 4.5 amps.  Is there a more powerful module?
Title: Re: Lamp Module Melt down
Post by: Brian H on December 21, 2009, 06:43:16 PM
The module is good for 15 amps pure resistive. Problem is cold bulbs and surge current.

I looked at a few other modules from other manufacturers. They all limited incandescent loads to a lower wattage.

ACT RP124 15 amps resistive; 600 watts incandescent.

Insteon ApplianceLinc 15 amps resistive; 480 watts incandescent or inductive.

Wayne Dalton ZWave Module HA-02WD 15 Amps resistive 8.5 Amps tungsten bulbs.
Title: Re: Lamp Module Melt down
Post by: mike on December 21, 2009, 06:49:56 PM
Good catch on the poor connection at the plug tabs themselves.  

We recently moved our small business to a city from home and had a fire dept. sneak inspection - seems they inspect all businesses for safety in cities...  anyway, we quickly were dinged for all extension coreds - not allowed!  period!  the small multi connector end you plug into apparently is cause of a majority of electrical fires we learned!  a power strip is ok but not an extension cord.  good info.  your experience seems to back this.

second, I had a x10 small 5 amp noise filter catch fire and shoot 12" flames that charred the 2x4 wall stud next to the outlet - for the same reason as yours!  NO INTERNAL FUSE AND BAD 120V TAB CONNECTION into the regular outlet!  pictures showed the filters 120v male prongs must of heated from bad 4.5amp load and burned the pcb right away - luckily I was in the room at the time a month ago and saw it happen - used 1/2 a fire extinguisher to put out the flames!  subsequently removed ALL x10 noise filters and replaced with smart home better quality and fused units.  my pictures look like yours - will send if anyone wants to see.
Title: Re: Lamp Module Melt down
Post by: Brian H on December 21, 2009, 07:09:53 PM
The LM465 also has one of what looks like the exact same coil in it as the XPPF has three of.
Title: Re: Lamp Module Melt down
Post by: rperego on December 21, 2009, 11:36:43 PM
I agree the rating is strange.  An extra 10 amps for inrush seems like a lot.
Title: Re: Lamp Module Melt down
Post by: -Bill- (of wgjohns.com) on December 21, 2009, 11:46:14 PM
Never measured it myself, but my understanding is that an incandescent filament is nearly a dead short when power is first applied and increases in resistance as it heats up.

 >!
Title: Re: Lamp Module Melt down
Post by: HA Dave on December 22, 2009, 11:49:12 AM
You guys are talking in AMPS... like making heat really requires that much. I know the little halogens that I use in my lawn lamps get really warm (will take your skin off). And they only use 10 WATTS at 12 Volts. That's not even a whole [1] AMP... is it?

I heard on one of the news channels that 10,000 homes will suffer damage or be destroyed this December due to Christmas lights (and there misuse). That sorta makes it sound like it might not be all that hard to do.
Title: Re: Lamp Module Melt down
Post by: gator.bigfoot on December 22, 2009, 12:43:20 PM

Power (Watts)=Voltage (E) X Current (I) 

This is for purely resistive loads.  When you get into inductive loads then it is a whole new ball game.  But for the most part most home applications will still follow this formula.

So in you case 10W/12V = 0.833 amps

One string of 70 (7 watt) lights 7X70= 490 watts        490 watts/110 volts= 4.45 amps

One 100W light bulb                                              100/110 = 0.9 amps

Four Halogen 50W bulbs                                         200/110 = 1.8 amps

Most fires occur because extension cords are overloaded.  Most extension cords are not rated for more than a 10 amps.  They use 16 or 18 gauge wire or even smaller.  Check your load tables

Wire    Current max at 110V
gauge
22       5A   
20       7.5A
18       10A
16       13A
14       17A
12       23A

With extension cords comes another danger.  Frayed wires.  Most extension cords are in poor shape.  They are already poorly made, with poor quality connectors.  Then you add your load to it, walk on it, the kids run their toys over it, it is hidden under a carpet.  It's no wonder there are fires. It is actually more of a miracle that there are not more.

Now we have another factor involved here and that is the length of the wire.  This adds resistance.  Resistance adds extra load.  All of that turns into heat.  Which needs to dissipate.  Too much heat equals fire. 

Years ago I worked for Square D.  The first thing one of my co-workers showed me was a suitcase (for trade shows) with a transformer in it and switch a receptacle and a bunch of breakers.  The transformer was connected to a 110 volts and the output voltage  of the transformer was very low(2 volts).  The current output of the transformer was around 200 amps.  The display was intended to show how fast different breakers trip.  By inserting a paper clip into the outlet (dead short) the switch was turned on.  With every single breaker manufacturer on the market the paper clip caught fire.  All but with the Square D breakers.  With theirs you could plug the paper clip in the outlet while the power was turned on.  Now granted not everyone will do this and the test was biased toward their breakers, but the intent of the display was to show what can happen with a frayed extension cord.  Once you get into very few wires and a high load it will draw a lot of extra current.  Enough to start a fire, as the paper clip demonstrated.  Needless to say I went home and switched out my breakers.

Title: Re: Lamp Module Melt down
Post by: JeffVolp on December 22, 2009, 01:13:05 PM
Those pre-lighted Christmass trees can pull a LOT more power than you expect.

We had always used a lamp module for the Christmas tree lights back East.  6 years ago we bought a large fake tree from Costco.  Not thinking that those little lights would pull much power, I plugged it into the lamp module like before.  The lamp module worked, but I was surprised by how warm it got, even with the bulbs dimmed.  (We run Christmas decorations at 60-70% brightness.)

I split the load between two lamp modules, and they worked fine.  This year out of curiosity, I measured the tree at full brilliance with the Kill A Watt.  I couldn't believe that tree was sucking over 700 watts of power!  Even dimmed to our normal level it was still pulling about 500 watts.  While the tree does produce a fair amount of light from all those tiny bulbs, it produces a tiny fraction of what seven 100W incandescent bulbs would do.  I think it is due to the shunt resistors in the bulbs that keep the string from going out if a filament burns out.

The bottom line is be careful.  These things may pull a lot more power than you expect.

Jeff
Title: Re: Lamp Module Melt down
Post by: Alan V on December 22, 2009, 06:42:51 PM
I think it is due to the shunt resistors in the bulbs that keep the string from going out if a filament burns out.

I don't know about your light strings, but most now use a better mechanism when a filament burns out.  There is a wire covered with an extremely this coating of insulation that overlaps a metal post in each bulb.  When a filament burns out, the wire sees the full 120 VAC across it.  That voltage is high enough to arc through the insulation and weld the wire in place, thereby completing the circuit.

It's a very clever cheap way of keeping the strings lit if a filament burns out.  If this happens to too many bulbs in the string, then the remaining bulbs will see a higher voltage and may burn out faster than they would normally.   
Title: Re: Lamp Module Melt down
Post by: Dan Lawrence on December 25, 2009, 10:53:53 PM
What's amazing is I have Lamp Modules that I've had since the late 1980's when I was introduced to X10 by a good friend of mine that have been in continuous service for over 20 years without a fault.   :)%