Discuss Electrical fire in the Security Alarms, Door Entry and CCTV (Public) area at ElectriciansForums.net

Welcome to ElectriciansForums.net - The American Electrical Advice Forum
Head straight to the main forums to chat by click here:   American Electrical Advice Forum

i=p/u

-
Arms
Reaction score
801
got call out to fire at property, plug top burned and cable to alarm clock all on fire , circuit on rcbo, what's going on? Dog ---- or what
 
Its a bad something. But you are/have been on site, you are the best judge as to the fault!

I am not sure what you are asking. Are you wanting to know why the RCBO did not trip?
Was there a fuse in the plug, Or is it a wall wart powersupply thingy?
Did the fire start at the plug? Or at the clock?
Was it only the top of the plug that was burned, was there any damage to the plug bottom?
 
On an alarm clock that is bad, the load is so small that there must have been something else plugged in before that wrecked the socket/plug connections and then the resistance was high enough to allow the clock load to cause the overheating. If the clock was class II and there was no earth in the supply cable to cause the RCBO to trip this is just about possible.
 
Any amount of arcing will cause heat, even on low current appliances.
 
I'm not convinced. A clock/radio might take 5W at 0.7pf i.e. 31mA load via the faulty contacts / connections. If their resistance reached 1 kilohm it would cause a heat dissipation of around one watt, which would warm the pin but isn't enough to set fire to anything. Have you ever seen an actual burn-out, caused by load rather than flashover, on a circuit carrying a small fraction of an amp? Scorched plug on a table lamp? Theoretically possible but very, very unlikely. By the time contacts get so loose / corroded that they could heat up with that load, they usually go open-circuit completely or so intermittent you know there's a problem because you can't get the load to stay on for more than a second at a time.

If it was a rewireable plug, I would be more inclined to think it was badly wired, there was a stray wire strand just out of contact. The flex moved, the short occurred, drew an arc which charred the plug and the heat was conducted up the cable.
If not, and/or the device was not of a reputable brand, then the cable may be substandard and the insulation broke down, and the arc spread to the plug.

Or, there's some other totally unrelated factor that you haven't been told about! I agree there's no particular reason for the RBCO to have tripped. Sharp, detailed pics would be very interesting...
 
Seems its possible I remembered seeing this on another forum I use (non electrical) so did a simple search.

"My new clockradio set on fire last night!

Basically bought a new clock radio as it was on offer for about £14. Its a goodmans one with a couple of usb ports on it so you can charge you phone.
Been using it about a week and last night pressed the alarm button to activate and went to sleep.
About 30 mins later the mrs is asking me if I can smell TCP and I could and it was very strong. We had the fan on in the room and sometimes you get strange smells from outside and the waft through via the fan so didnt think much of it.
A few mins later the tcp smell turned to burning and then notice smoke pouring out of the clock radio and it was starting to melt and you could see a small flame.
I pulled the mains out and burnt myself on the radio lol.

I dont understand why it done it. It only gets used for an alarm and havent used the usb ports yet.
The power supply is only 5v aswell to it.. Bizarre!!"

Was it a goodmans?
 
I've no doubt the clock itself can burn up, anything with a power supply or transformer in can although the materials it's made of should be self-extinguishing. The question is how can the plug / cable overheat when the clock doesn't?
 
Yeh, pictures would be great just because of us being nosey.
External factors? Cigarette end smouldering if no other explanation comes.
@mykey gets 2016 award for most exciting story told with dramatic licence - TCP! Laugh out loud.
 
As the place was a mess on arrival, all I had do was disconnect ring and return when they have cleaned up or new order comes out.

The only pic I took wasn't great. Reading from your replys il add , they had an extension lead plugged into
etension lead(1m 4 ways) the plug top was burnt the cable was burnt and the alarm was burnt, id say was possibly class 11 item.

View attachment 35067
 
You didn't mention the clock was burnt, only the flex and plug. There seems to be a lot more involved there than we imagined. Do you think the clock started the fire, and if so, what makes you think that?
 
Theres a 4 way extension lead there as well.
 

Reply to Electrical fire in the Security Alarms, Door Entry and CCTV (Public) area at ElectriciansForums.net

OFFICIAL SPONSORS

Electrical Goods - Electrical Tools - Brand Names Electrician Courses Green Electrical Goods PCB Way Electrical Goods - Electrical Tools - Brand Names Pushfit Wire Connectors Electric Underfloor Heating Electrician Courses
These Official Forum Sponsors May Provide Discounts to Regular Forum Members - If you would like to sponsor us then CLICK HERE and post a thread with who you are, and we'll send you some stats etc
This website was designed, optimised and is hosted by Untold Media. Operating under the name Untold Media since 2001.
Back
Top
AdBlock Detected

We get it, advertisements are annoying!

Sure, ad-blocking software does a great job at blocking ads, but it also blocks useful features of our website. For the best site experience please disable your AdBlocker.

I've Disabled AdBlock