Burnt Main Downstream Neutral

[Squid]

Sheaving???

Sheathing, damn spell check on the Mac + Sausage Fingers.......

 

[The Ghost]

"guilty knowledge"

I suppose we are now implicated by also knowing and share the guilt. Oh oh!

 

[ennaress]

There are two immersion heaters in one insulated tank. The first is a Heatrae Centerbrand Superloy 800 and is 2.8kW @ 230V. The other is a Backer 2.7kW @ 230V.
The owner was told that evening and I disconnected one of the immersions. I then replaced the burnt neutral with a new tail and terminated it to one of the non-melted points as a temporary, safe fix. The EICR has amongst over 20 other observations, a C1 for this....obviously!
A replacement 7671-3 CU is going to be done. I'll also run the immersions on an indep circuit protected with a 20A breaker as will the oven.
No - the outer sheathing had melted and globbed down the conductor.
Yes - the R1-R2 were fine but rubbish / null IR readings which is a real head-scratcher and I'd welcome any sensible avenues of investigation.

 

[westward10]

What do you mean by null IR readings.

 

[Pete999]

There are two immersion heaters in one insulated tank. The first is a Heatrae Centerbrand Superloy 800 and is 2.8kW @ 230V. The other is a Backer 2.7kW @ 230V.
The owner was told that evening and I disconnected one of the immersions. I then replaced the burnt neutral with a new tail and terminated it to one of the non-melted points as a temporary, safe fix. The EICR has amongst over 20 other observations, a C1 for this....obviously!
A replacement 7671-3 CU is going to be done. I'll also run the immersions on an indep circuit protected with a 20A breaker as will the oven.
No - the outer sheathing had melted and globbed down the conductor.
Yes - the R1-R2 were fine but rubbish / null IR readings which is a real head-scratcher and I'd welcome any sensible avenues of investigation.

Can you explain the last paragraph in greater detail? R1+R2 were fine but rubbish/null IR readings?????

 

[static zap]

/ null IR readings which is a real head-scratcher and I'd welcome any sensible avenues of investigation.

Measured on what ?
, would it progress no further -Error ?

 

[davesparks]

I'll also run the immersions on an indep circuit protected with a 20A breaker as will the oven.
.

Both immersion a on one circuit? How's that going to work?

 

[Dave OCD]

Wire them through a 20a 2 way switch so one can have a rest every other day.

 

[davesparks]

To cover you behind send the customer a Danger Notice without delay. It looks too far gone to be cured by tightening the screw up. What do you mean by IR is open circuit (OC) ?, if it is how have you got satisfactory r1+r2 ? You have what is known as "guilty knowledge" of a potential fire risk. Ideally tell them it must be isolated and the C.U. replaced immediately, I realise that may not be practical, so send the Danger Notice and make it their problem not yours ! Sorry if I sound like an arse but where there's a blame, there's a claim !! .

I wouldn't rely too much on this 'danger notice' to cover your arse, I think it is more likely to be used to prove that you left a known danger in place rather than help you get away with it if the worst did happen.
Don't forget that this 'danger notice' (if you are referring to what I think you are) is something invented by the nic which has no basis in the regulation or law.

 

[davesparks]

There are two immersion heaters in one insulated tank. The first is a Heatrae Centerbrand Superloy 800 and is 2.8kW @ 230V. The other is a Backer 2.7kW @ 230V.
The owner was told that evening and I disconnected one of the immersions. I then replaced the burnt neutral with a new tail and terminated it to one of the non-melted points as a temporary, safe fix. The EICR has amongst over 20 other observations, a C1 for this....obviously!
A replacement 7671-3 CU is going to be done. I'll also run the immersions on an indep circuit protected with a 20A breaker as will the oven.
No - the outer sheathing had melted and globbed down the conductor.
Yes - the R1-R2 were fine but rubbish / null IR readings which is a real head-scratcher and I'd welcome any sensible avenues of investigation.

Only the lower heater should be connected in a two immersion heater cylinder if no off-peak/E7 supply is available.
The upper heater is only there to be a boost element in an off-peak/E7 setup. It will do little to no work if it is switched on at the same time as the lower heater, the heat from the lower heater will quite quickly operate the thermostat of the upper heater and switch it off. Also with modern immersion heaters the lower element can operate the overheat trip of the upper element and switch it off permanently (until reset)

Why are you quoting the 230V power ratings? The public electricity supply in the U.K. is 240V, the mythical 230V only exists on paper and not in the real world. These immersion are will be operating at 3kW and using the lower power ratings will lead to you designing and installing a circuit with a small overload which is a dangerous situation.

What is a rubbish/null IR reading? All of the IR testers I have used have only ever had a numerical scale so I haven't a clue what those readings equate to.