Consumer Unit Fire - Electrical Fire - Fuse Box Fire

You may have seen these pics posted on another forum last year. It was a fire at the intake position of a country house that was caused by a loose connection on one of the supply phases. The fire started around 1am when the 19Kw water storage heater kicked in. All the smoke alarms had no batteries and the occupiers were luckily woken by the crying toddler who's bedroom above filled with smoke.

1st pic, main view

2nd pic, garage door opener

3rd pic, board No1

4th pic, disused storage heater board

This was a TT system yet the only Rcd was on a disused storage heater board

I have many more pics if anyones interested.

Beats my 13a plug top meltdown !!!

nasty

I noticed i never posted the other pics of a job i did a year or two back .

The fire was caused by a poor connection on one of the phases into the head. TT 3 phase overhead supply with ali 4 core cable. The night storage boiler pulls 92 A on one phase . Normal storage heater on another phase & domestic supply on the 3rd.

Everynow & then the main fuse would blow and it did 2 days before the fire. The engineer tightened all the cables and from what i could see they were bare ali into a brass connection .

The yellow tags are where the fire investigation team took the metering equipment away.

All the smoke detectors were open with no batteries and cobwebs accross them. The 5 year old daughters bed was right above this and the smoke woke her up and she started coughing so much the parents came in to see what the matter was.

Overview



Bit of heat







Storage heater board





This was the time clock for the off peak heating



Off peak contactor



Swa running across ceiling



Garage door opener





Switch fuse for extension

Why oh why do people take batteries out of smoke detectors they should be shot. That girl was so lucky it could have been a different story.

That is some fire,,

So,,, who paid for this lot to be fixed then? Seeing as it was a DNO issue

The common theme here, (and another recent thread) is loose connections and fire starting at the INTAKE.

That's outside the scope of us electricians, and the responsibility of the DNO.

Is this pointing to a need for periodic inspections by the DNO of their supply side equipment?

It seems prudent householders and landlords may get a PIR done on the consumer side of an installation, but nobody is regularly checking for problems with the incoming supply and metering.

If the DNO are not going to do it, then yet again this points to a NEED for electricians to cut seals, pull the main fuse and check the connections at the head and in the meter so they can check the WHOLE installation as part of a PIR.

I'm sure we have all seen installations where it's clear the supply side has not been touched for 30 years or more (rubber / cotton covered tails for instance), so clearly regular inspection and maintenance is woefully lacking by the DNO in some cases.

And if the fire investigators PROVE the fire started in the supply equipment, can the house insurance company pass on their bill to the DNO?

And are the DNO prosecuted by the HSE for negligence?

Discuss.

The owners paid us to fix it all. We made a new cabinet and mounted all the boards to the right of the existing, so this could be left as evidance. The majority of the cables came from that direction. The burnt stuff was left as you see it as EDF & Seimens were arguing whose fault it was. Last i knew the owner had to sue both parties to get his money back. The first job i did after the power was reinstated was to wire a smoke alarm system into every room.

r.e Dave`s comments above.

Though I applaud and, to a great extent agree with the sentiments......they`re never going to sign off on that. I`m not sure I`d even want `em to - that would make problems like this OUR responsibility.

Further, HED connections are live - we`re therefore excluded from being allowed to verify the integrity of those connections.

Possibly thermographic surveying would work - but this is off-peak kit; so you`d have to do such a survey in the middle of the night - a loose connection drawing zero current won`t get warm.

DNO`s ought to be periodically checking / upgrading their equipment; and they should be liable for the supply to, and in, the HED.

RECs should then have liability for meter tails & connections to an approved "REC2" type iso; which it should be their DUTY to provide.

We then have liability from that point out; subject to whatever limitations are stated on our cert.

And Yes, HSE ought to be going after the relevant company, if it is proven to be negligence on their part(s)

I don`t want the extra hassle of determination of conductor material of the incoming live cable, the HED construction, relevant tightening torques; and the possible implications & ramifications arising from this.

There is another argument against it as well mate: "fast-track" sparks. They are considered "qualified" to perform DPIRs (DEICRs now, I suppose) ; but many would not be capable of taking such responsibility, even if their insurance would cover it, and HSE would have a field day!!!!!

KME

I had to make a report out regarding my opinion of the fire. i made it clear it was my opinion based on what could be seen with no tests carried out. The main thing was this house was down a country lane. I had a chat with some neighbours and they all had economy 7 heating. From the overhead supply you could see all the adjoining properties were on the same phase & that was also the phase this houses heating was on.

I wondered what the voltage dropped to at midnight when 500 odd Amps kicked in. The lower the voltage, the more current thats drawn and thats why the main fuse may have been blowing. The Seimens engineer that was there two days earlier told the customer he had tightened all the connections, it appeared to be an aluminium supply cable into a standard brass terminal connector on the head. I think this had cut into the cable and weakened it. It is clear from the pics the source of heat was the L1 fuse on the head, which the electric boiler was connected to.

Slipshod, you mention the "boiler" was a 90A load, so that's 21KVA load.

now MOST domestic single phase supplies are only "rated" at 16KVA

I know this was a 3 phase install, but what was it's offical rating? 16KVA per phase, or 21KVA per phase?

There might be an argument that the consumer was drawing more than the supply was "rated" for.

My own house is an oddity. The supply is "rated" at 16KVA, but it has a 100A fuse and I not infrequently draw 18KVA without issue. but surely if it's "rated" at 16KVA it should have a 80A fuse?

I will have a look back to see if i can find the details of the heater. I have a feeling the total rating of the boiler and some storage heaters was around 90A so the boiler may have been within the allowed tolerances. All the heating was single phase, i had a look in the boiler controller to see if it could be 3 phase but no.

Property in doncaster last year...5WW did a pir, aico fire alarms with remote senders fed from the light in each room. Not ideal but in no way unsafe, "there connected illegally they have to be on their own circuit" so he disconnected them all.....................

Jono, the 5WW was being a plank, (My boot would be finding contact with a set of his cheeks if I met him) I have the Aico install guide for contractors that they do, and they give similar advice as being safe in the handbook.

AndyGuinness

I wondered what the voltage dropped to at midnight when 500 odd Amps kicked in. The lower the voltage, the more current thats drawn and thats why the main fuse may have been blowing.

Click to expand...

heating elements have a fixed resistance. the lower the voltage, the lower the current flowing. same as showers are rated to x amount at 240v, but less at 230v

---------- Post Auto-Merged at 13:23 ---------- Previous post was made at 13:21 ----------

Property in doncaster last year...5WW did a pir, aico fire alarms with remote senders fed from the light in each room. Not ideal but in no way unsafe, "there connected illegally they have to be on their own circuit" so he disconnected them all.....................

Click to expand...

cant see any problem with that. at least if the power fails to the lights (& the alarms), then it usually get noticed & fixed quickly

I had thought about that Andy, but i cant believe when all that current draw kicks in the voltage doesn't drop ,which affects many things