New flat immersion heater melting wires

[SamJames]

Just thought I'd update everyone on the current situation. After a lot more pressure on the developers, they've sent over the NICEIC certification again which they claim proves that the wiring was sufficient at 1.5mm².

We are now stuck again as our electrician claims 2.5mm² is necessary and 1mm² was installed whilst the developers say that 1.5mm² was installed and sufficient. Since they have their certificate, they are satisfied they've done nothing wrong despite the wiring melting. Everyone here has been extremely helpful. Is there a correct answer?

 

[Agile]

1.5 mm is adequate ( just ).

But you think its only 1 mm and that is not. The fact that it has melted rather proves that.

But you still talk in isolation. What is going on in the other flats?

Tony

 

[SamJames]

Since this thread started, I have asked a few of the other flats and no one else has reported any of the same issues. The flats are all fitted with vented cylinders which are only slightly raised above ground level so all the flats have very poor hot water pressure. As far as I'm aware, we're the only flat with a pump fitted so I think we use far more hot water than other flats - could that mean we are more susceptible?
2"
The developers have stated that as the certificate proves it was adequate, the melted wiring was just "bad luck" and something that just "happens". I don't know how else to convince them otherwise.

 

[Agile]

The proof is in the size of the cable as measured.

I suppose you have now lost the original cable.

The heat is generated all the time the immersion is on.

It does take a while for the temperature to build up, perhaps 15-30 minutes at most!

Seems that as there is no evidence from other flats then you have been unlucky.

I like exact measurements of cable sizes and not some electrician who looks at it and says its XXX. You cannot take that to court! If you took that electrician he would probably not appear as a very professional witness.

Tony

 

[SamJames]

Luckily I have retained all the original cabling and everything that has been taken out. I don't have a caliper or any means to measure the difference between 1 and 1.5mm though so have taken the electrician at his word. Obviously, as the wiring has melted I trusted that he was right in that the wiring was too thin! Is it possible for "adequate" wiring to have been installed and yet still melt under normal use?

 

[SamJames]

I'd also like to say thank you to you Tony, for your fast responses and far clearer explanations than I've had from anyone I've had to deal with. If only you had fitted my flat!

 

[endecotp]

Luckily I have retained all the original cabling and everything that has been taken out. I don't have a caliper or any means to measure the difference between 1 and 1.5mm

If you look carefully you may find printing or embossing on the sheath.

 

[DP]

Sam, when you say cable melted, do you mean the whole cable or just the termination

Count the strands in the conductor

Presence of certificate, what if someone has issued a certificate but not carried out full check?

 

[BigSnoopy01]

Contact the niceic they warranty there members work and may be interested in taking a look.

 

[SamJames]

If you look carefully you may find printing or embossing on the sheath.

Do you know, I've had this cabling for a few months now and, despite looking for writing before, didn't notice that there was a slight embossing on it! It says this:

Pamukkale Kablo H05VV-F 5G 1mm² Basec TSE <HAR> 2013 PX95

I'm assuming that means it's 1mm²?

Sam, when you say cable melted, do you mean the whole cable or just the termination

Count the strands in the conductor

Presence of certificate, what if someone has issued a certificate but not carried out full check?

Just at the terminations at the timer and spur. I don't have it at hand but will count when I'm at home, thanks.

Contact the niceic they warranty there members work and may be interested in taking a look.

Just want to double check what all that writing on the cable means and if I have confirmation that it is indeed 1mm² then I will do.

 

[endecotp]

Yes, that says what you think it says.
I don't think the other codes are very interesting but someone may be able to decipher them.

 

[Agile]

Cable ratings are given for different installation methods, such as in free air with more cooling, clipped to a flat wall etc.

But where it goes into a fitting the cooling air flow is restricted so that is where it is likely to over heat. Also many terminals are not very low resistance and create more heat.

1 mm cable is probably rated at about 8 amps whereas the immersion heater current taken is about 13 amps.

I think you have a very good legal claim against the builder/developer. That's a common law claim and not under any warranty, actual or implied.

Thanks for noticing that I write clearly. I used to work for BBC Engineering and one of the advantages is they sent me on a three day technical report writing course. Also later a three day presentation course although that was a long time after it would have been the most beneficial. So I had to do my best at presentations without the benefits of specific training.

Tony

 

[DP]

Just at the terminations at the timer and spur. I don't have it at hand but will count when I'm at home, thanks.

In that case may just be lack of tightness of termination. Cable overheat would heat the entire cable, it would be like someone had set fire to it

 

[DP]

1 mm cable is probably rated at about 8 amps whereas the immersion heater current taken is about 13 amps.

11 to 15 amps is what I make it

 

[endecotp]

Just at the terminations at the timer and spur. I don't have it at hand but will count when I'm at home, thanks.

In that case may just be lack of tightness of termination. Cable overheat would heat the entire cable, it would be like someone had set fire to it

That would require that two electricians had not tightened then sufficiently.
The cable is known to be undersized. It is going to melt first inside the boxes where convection is limitted.