EICR in Church - Low IR in MICC heater circuits

[ringer]

Recently done a EICR in a church and about half of the heater circuits (tubular heaters fed by MICC routed under the floor) had low IR, typically 0.18 to 0.61 Mohms. There is a lot of damp in the floors, and I have to explain to the customer why the circuits are failing the tests so that they can then justify commission of rectification (i.e. rewire the affected circuits). How can I explain, in plain english, what might happen to these circuits because of the low IR? What is likely to happen as a consequence of the insulation breaking down? Apart from the OCPD disconnecting the circuit?

 

[MarkieSparkie]

With most of those old church tube heater circuits, it's the tube heaters that are damp and causing the low IR not MICC. Try running the heaters for half an hour and then retest, in my experience the IR will be back to normal and compliant levels.

 

[Brightspark2]

If the heaters where still in circuit it will be them causing the low reading...

If it was the cable it would eventually short out and they would lose power to the circuit...in which case would need re-wiring anyway...

If it is the cable check the ends, if it hasn't been terminated correctly it can get damp and cause the low ir reading, there's a little trick with a lighter you can do to work it out then it just needs re-terminating...

Sent from my Xperia S using next doors WIFI.

 

[ringer]

I made sure the DP spurs for all heaters were off before measuring. Last set of test results from 5 years ago had low readings as well, but back then 0.5Mohms was acceptable. The acceptable limit is now higher, and there would also appear to be further deterioration in the condition of the wiring.

I am aware of the lighter trick though have never had the opportunity to try it before. Bit wary of pots/seals breaking though.

Seeing as how a rewire is going to cost several thousand of pounds, I am going to suggest they pay me a couple of days at my daily rate to investigate further. It may just be certain small sections that need replacing, but there are lots of JBs under wooden flooring with great big heavy pews sitting on top, so quite a bit of work involved. Presumably if insulation is failing, before enough current flows to trip the ocpd they will be using quite a bit of energy in the 'extended' heaters.

 

[Guest123]

It does sound like damp/moisture getting into the system somewhere along the way. As said, try running the heaters for an hour and see what results you get then. This may give you an idea of the worst affected section etc. Damp in churches will always be an issue, particularly if the MI is run under the flooring.

Perhaps recommend a C3 and investigate further if permitted.

Sent from my HTC Desire C using Tapatalk 2

 

[ringer]

C2 and further investigation required is what I had in fact given on my report for this particular issue. There were other less serious issues as well. Have just come away from meeting with client and have got a week's work doing further investigation and remedials, with the potential for further remedial work dependant on what my investigations turn up.

Did warn them worst case scenario is to rewire heater circuits at cost of up to £10k. On that basis they are more than happy to pay me to investigate further

 

[Guest55]

Well if the church already has a PIR cert warning the pyro on its last legs then they will probably continue to do nothing until there is complete failure of the circuit (s) as replacement is going to be very expensive , cant say i blame them really.
If it was me doing any subsequent work , i'd be very wary / reluctant to try and do patch repairs and small replacement of the existing micc , i'd be pushing for full rewire of the affected circuits.