BS7671 test and internal electric heating

[Soup]

Hi all
I'm unsure if it's appropriate to post this on this board but I wanted to get opinions from people in the industry on a sticking point with an electrician I currently have.

a bit of background - I am letting out my flat and as part of the pre-let safety checks I decided to go ahead and get a "periodic test" carried out on the flat - a test under BS7671 on the internal electrics.

The electrician did the report and said the circuits were satisfactory, supplying me with an EICR on completion.

On the report, it stated he was unable to test 2 things :
1) The off-peak water circuit, as there was no power on the circuit due to it being tested during the day. I was fine with this...; and

2) The central heating circuit. I have Flexel Ceiling Heating in the flat and was quite specific about asking him to test this from a safety point of view. He said as there were timers in the circuit he was unable to test this (I have two 24-hour "pin-controlled" timers on the hallway wall).

The central heating point is where I am having the issue. Following further discussions, he said that as well as the issue with the timers, the heating did not seem to be powered as it was being fed from a night-time supply, external to my flat.

This struck me as a bit odd - I know my heating works (a friend of mine went to the flat on my behalf to test it after the electrician had done the BS7671 test and said it seemed to work fine) so I'm a bit puzzled why he couldn't test the heating circuit. Maybe the night-time supply could be explained by Economy 7?

The electrician also said he couldn't work out how to turn the heating on as well - so surely if he had actually turned the heating circuit on (there's a main on/off switch on thermostat in the lounge of the flat) then he should have had some sort of electric current reading to confirm whether it was satisfactory within the boundaries of the BS7671 test?

His final reply to me recently was:
"I offered a ‘Periodic Test’ of the flat’s electrics as prescribed by BS7671. This is a test of the various circuits, specifically earth loop impedance and insulation resistance. This testing does not include appliances, and also excludes central heating (systems) which is effectively an appliance.
The power circuit cable from the consumer unit in the hallway goes straight into the timer boxes and these appeared to be preventing that circuit from being tested. There is no requirement under BS7671 to have to dismantle apparatus in order to test which appears to be the case here.

As I said, all other circuits check out fine, and on the basis that this circuit is of the same vintage, and nothing has been modified, there is absolutely no reason to be concerned.
So if you have an absolutely specific cause for concern about the ‘circuit’, then that would be a separate piece of work, and wouldn’t come under the remit of ‘Periodic Testing’.
If it’s the case that you want a general central heating service/ health check, then this is something that is definitely outwith the scope of periodic testing, and is not a service I can offer."

What do you guys think - is he fair in his comments, or he is simply trying to avoid having to going back to test the circuit again with the heating switched on to see if it would have a different result? He seems like a stand-up guy and the other work he has done for me has been fine to date.

Thanks in advance :army:

 

[Darkwood]

Hi Soup and welcome to the forum from the staff

 

[HappyHippyDad]

Hi Soup,
I would personally have a good chat with the homeowner before undertaking the EICR so that you know exactly what you are getting from me and we avoid these kind of scenarios. However, it sounds as though you did mention the central heating before hand.
An EICR generally takes around 3/4 (approx) of a day to complete (based on a 3 bed property) and then another hour (at least for me) to complete all the paperwork.
I would test the Insulation resistance on the central heating, along with one or 2 others tests which it sounds as though he did (these are dead tests, completed with the power off). This would be a test to see if all the wiring upto the boiler is ok. I would not be testing your combi boiler (or whatever appliance it is) iitself.
My instinct is to think he's done an OK job but there has been a lack of clear communication.

 

[davesparks]

If you specifically asked for it to be tested before he started/took the job on then he should have tested it, regardless of what would normally be included in periodic testing.

Pin type timeswitches operate mechanically rather than electronically and almost always have an override control, or failing that just adjust the time to turn it on!

'Dead tests' (those requiring the supply to be isolated) can be carried out on the off peak circuits exactly the same as normal circuits.
Depending on the nature of your off peak supply it is almost always possible to carry out the live tests without the off peak supply being live

 

[Soup]

Thanks very much for the responses guys, really appreciate it.

I should have clarified that my property does not have gas, it is purely electrical from a power point of view so no boiler, simply water tanks.

I did have a detailed chat with him beforehand about the heating system - although I wasn't asking him to test the functionality of the heating itself and whether it was in good working order, I merely wanted to ensure the electrical circuit that related to the heating (and other in-built appliances such as extractor fans) was tested - and from our discussions I thought that it would be.

He's basically said that he couldn't test this particular circuit due to the timers and also because of the lack of power - which is why I queried it with him when my friend said the heating was working fine, there must have been power for it to work - so surely turning it on when testing it would have solved this issue, unless the timers in the circuit prevented this BS7671/EICR test irrespective if the heating was on or off.

The comment from one of your replies : "Pin type timeswitches operate mechanically rather than electronically and almost always have an override control, or failing that just adjust the time to turn it on!"
is what it comes down to - my underlying feeling is that he couldn't/didn't work out how to turn the heating on, thus no power to test that circuit properly - something which could have been rectified by a quick phone call to me asking how to turn the heating on!

Based on the above, do you think I should leave it or push this further?

 

[Richard Burns]

I would feel that the electrician has completed a normal periodic test of your installation.
However if the heating circuit was specifically agreed as being part of the testing this should have been included (up to the point of the timers).
It sounds like he was having difficulty with this part of the installation and from what he says I would not be confident that he would be able to complete this part of the testing.
I would tend to agree that if the installation is compliant in other respects that the heating could probably be complaint as well but if you have a specific concern about it then it may be a solution to get someone else in for an hour to cover that circuit on its own.

 

[Soup]

I would feel that the electrician has completed a normal periodic test of your installation.
However if the heating circuit was specifically agreed as being part of the testing this should have been included (up to the point of the timers).
It sounds like he was having difficulty with this part of the installation and from what he says I would not be confident that he would be able to complete this part of the testing.
I would tend to agree that if the installation is compliant in other respects that the heating could probably be complaint as well but if you have a specific concern about it then it may be a solution to get someone else in for an hour to cover that circuit on its own.

Thanks for that - it might indeed be a good idea to get someone else out just to look at the circuit(s) he couldn't test properly.

Interestingly, I have since found an electrical test report which I had done when I bought the place in 2008 - seems to be the same type of test (Periodical Inspection Report under BS7671). The electrician who did that test at the time managed to do a full test of all circuits, including the heating - so I'm going to send it to this other guy and ask him "if he could do it, why can't you?" (although I'll try to word it more politely than that!) :laugh3:

 

[Soup]

Right, I think I've nearly got to the bottom of this with the electrician now.

When I asked him about the various differences between the 2008 report and his, he noted the following:

- The 2008 report showed a very low (almost non-existent) for insulation resistance on the heating circuit - which would seem to imply that the other electrician also struggled to get a meaningful reading (or any reading at all) out of that circuit;

- The 2008 report did however show what appears to be suitable Zs readings for the heating circuit and the off-peak water, something which my current electrician hasn't able to manage. He's unsure how the previous electrician would have got such a reading given the lack of power and the switches/timers (ie isolation) in the circuit;

- I also queried why he hadn't tested the continuity (Ring final circuit continuity in respect of the "sockets" circuit, and R1+R2 continuity for all circuits) in his report, when the previous electrician had. His response was "There’s no need to do continuity testing on a periodic. If the testing of Zs and Insulation Resistance gives good results, then that really proves a safe circuit which is the aim of the exercise. BS7671 merely states to undertake ‘appropriate tests’. If another sparky chooses to do continuity, that’s up to him but it’s always down to discretion and appropriateness."

So his stance on the heating circuit seems to match up with the outcome of the 2008 report.

I'd be grateful if any of you have any comments on the 2nd point (regarding the inability to test Zs) and 3rd point (whether continuity testing is/isn't part of a periodic test)!!

 

[Richard Burns]

If there is no power to a circuit then for a periodic test this should be noted in the limitations section.
In this case it would be usual to do a R1+R2 test or an R2 test on the dead circuit to confirm protective conductor continuity, from these results and the Ze a Zs value may be calculated.
For your circuit in 2008 it may be that the Zs was calculated up to the point of the timers, if there is the possibility of gaining access to the conductor connections.
For periodic inspections there is no requirement to test the protective conductor continuity for a circuit if there is a valid Zs reading obtained as the Zs reading confirms protective conductor continuity. A lot of electricians will do the R1+R2 test or R2 test as this is part of initial verification and is very familiar and provides a secondary confirmation that there is a protective conductor present with low conductivity.

 

[newtothis]

Maybe you could contact the manufacturer, they might have some kind of list of approved testers for your ceiling heating system ?
Personally think you're flogging a dead horse pursuing the spark over this, if that's your angle, not sayin' it is of course.





Edit - corrected it for you ...Darkwood

 

[HappyHippyDad]

Right, I think I've nearly got to the bottom of this with the electrician now.

When I asked him about the various differences between the 2008 report and his, he noted the following:

- The 2008 report showed a very low (almost non-existent) for insulation resistance on the heating circuit - which would seem to imply that the other electrician also struggled to get a meaningful reading (or any reading at all) out of that circuit;

- The 2008 report did however show what appears to be suitable Zs readings for the heating circuit and the off-peak water, something which my current electrician hasn't able to manage. He's unsure how the previous electrician would have got such a reading given the lack of power and the switches/timers (ie isolation) in the circuit;

- I also queried why he hadn't tested the continuity (Ring final circuit continuity in respect of the "sockets" circuit, and R1+R2 continuity for all circuits) in his report, when the previous electrician had. His response was "There’s no need to do continuity testing on a periodic. If the testing of Zs and Insulation Resistance gives good results, then that really proves a safe circuit which is the aim of the exercise. BS7671 merely states to undertake ‘appropriate tests’. If another sparky chooses to do continuity, that’s up to him but it’s always down to discretion and appropriateness."

So his stance on the heating circuit seems to match up with the outcome of the 2008 report.

I'd be grateful if any of you have any comments on the 2nd point (regarding the inability to test Zs) and 3rd point (whether continuity testing is/isn't part of a periodic test)!!

With regards your first point, an insulation resistance reading is a dead test (conducted with power off) so your electrician could have done this test, I am unsure if he did or not? Also, a low insulation resistance result does not mean that he had difficulties obtaining the result, it means he tested it and that was the result he got. A result of 1MΩ or greater is acceptable, and a result of below 1MΩ means that circuit requires attention.

With regards your second point (the Zs readings) as Richard has said the original electrician may have just calculated this from looking at the Ze result and adding it to the R1+R2 result (so it could be obtained with the power to the heating circuit off). You could perhaps look at these 2 results (Ze and (R1+R2)) and if added together equal 'exactly' the result he has put for Zs then he 'may' have just calculated the Zs (unless coincidentally that was the measured Zs, but unlikely). Ze may be written as 'Zs at DB' on the report that you have.

So, with the power to the heating off your electrician would not be able to carry an actual 'measurement' of the Zs, but he could carry out an R1+R2 of this circuit and add it to the Ze (to obtain a calculated Zs).

Again, as Richard has said not all electricians will carry out a R1+R2 on a report if they get a satisfactory Zs so i dont think your electrician should be penalised for this, but an R1+R2 on the heating circuit would have been necessary as no Zs was obtained.

Lastly, it's very difficult to give 100% guaranteed advice without seeing the installation.

It would be interesting to know how long the electrician was there for and how much he charged?

 

[Risteard]

To get this into perspective, it is not a "periodic test". It is a periodic inspection. Inspection precedes testing, and is the more important aspect. (Many problems will not be located through testing.) The testing merely supplements the testing.

Also, I presume happyhippydad did not mean to suggest that an insulation reading of 1 Ohm would be acceptable!

 

[Leesparkykent]

To get this into perspective, it is not a "periodic test". It is a periodic inspection. Inspection precedes testing, and is the more important aspect. (Many problems will not be located through testing.) The testing merely supplements the testing.

Also, I presume happyhippydad did not mean to suggest that an insulation reading of 1 Ohm would be acceptable!

??????

 

[HappyHippyDad]

To get this into perspective, it is not a "periodic test". It is a periodic inspection. Inspection precedes testing, and is the more important aspect. (Many problems will not be located through testing.) The testing merely supplements the testing.

Also, I presume happyhippydad did not mean to suggest that an insulation reading of 1 Ohm would be acceptable!

Thanks for pointing that out Risteard! How embarrassing! Have amended.

 

[Risteard]

??????

LOL. I meant the testing merely supplements the inspection!

 

[GEOFF S]

The central heating system will fall outside the scope of BS7671 try BS EN 14336:2004. The fixed wiring upto the controls/? will be under BS7671

Cheers

 

[Leesparkykent]

The central heating system will fall outside the scope of BS7671 try BS EN 14336:2004. The fixed wiring upto the controls/? will be under BS7671

Cheers

It's not a water based heating system.

 

[GEOFF S]

It's not a water based heating system.

Thanks Lee, just saw central heating. That said, this productt will have its own product standard to which it needs to de designed, installed, commisioned and tested.

Cheers

 

[Soup]

Thanks everyone for your comments on this. It's quite confusing as a layman with no electrical knowledge/training so I'm trying to get up to speed here!

With regards your first point, an insulation resistance reading is a dead test (conducted with power off) so your electrician could have done this test, I am unsure if he did or not? Also, a low insulation resistance result does not mean that he had difficulties obtaining the result, it means he tested it and that was the result he got. A result of 1MΩ or greater is acceptable, and a result of below 1MΩ means that circuit requires attention.

It would appear the electrician who did my recent inspection has not done this test on the heating circuit - he has left all readings blank on the heating circuit and stated on the test sheet "unable to test due to timers in the circuit".

On the 2008 report, the results the electrician got on the heating circuit were 0.07, 0.08 and 0.07 for phase/neutral, phase/earth and neutral/earth respectively (for insulation resistance). R1+R2 was 0.25. Zs figure was 0.47.

As these figures appear to be below 1MΩ, what "attention" would this circuit would require in your opinion?

With regards your second point (the Zs readings) as Richard has said the original electrician may have just calculated this from looking at the Ze result and adding it to the R1+R2 result (so it could be obtained with the power to the heating circuit off). You could perhaps look at these 2 results (Ze and (R1+R2)) and if added together equal 'exactly' the result he has put for Zs then he 'may' have just calculated the Zs (unless coincidentally that was the measured Zs, but unlikely). Ze may be written as 'Zs at DB' on the report that you have.

So, with the power to the heating off your electrician would not be able to carry an actual 'measurement' of the Zs, but he could carry out an R1+R2 of this circuit and add it to the Ze (to obtain a calculated Zs).

Again, as Richard has said not all electricians will carry out a R1+R2 on a report if they get a satisfactory Zs so i dont think your electrician should be penalised for this, but an R1+R2 on the heating circuit would have been necessary as no Zs was obtained.

I can't find the Ze figure on either report, either shown as Ze or "Zs at DB". Does Ze relate to the total of the insulation resistance readings?

If so, that might work for the heating circuit - as per my point above, on the 2008 report I have readings of 0.25 (R1+R2) plus 0.07+0.08+0.07 (sum of insulation resistance readings) = 0.47 - which matches to the Zs reading on the report.

However, this calculation doesn't seem to work for the off-peak immersion circuit reading on the 2008 report - this has 0.11 R1+R2, then >500 on all 3 insulation readings. Zs total on this circuit per the 2008 report is 0.30.

It would be interesting to know how long the electrician was there for and how much he charged?

He charged me £90 (no VAT as not registered). Based on his hourly rate for other non-electrical work, that would appear to be 2 hours he spent doing the testing and completing the report/testing details on the summary sheets he gave me. This seems cheap (like the budgie) in comparison with what I spent on the 2008 report and the other quote I had for the work recently.

 

[Soup]

UPDATE TO THE ABOVE POST:

I've found the Ze readings on the reports!

2015 report (current report) = 0.04Ω

2008 report (old report) = 0.23Ω

So... looking at the 2008 report.... 0.25 R1+R2 +0.23 Ze = 0.48 (calculated Zs). Zs per the report = 0.47. So virtually exactly the same, like you guys said. Although that might still indicate the 2008 electrician managed to get a "normal" Zs reading of some sort as the Zs figures aren't identical.

So, I think I will go back and ask the current electrician if there was a reason why he didn't use the alternative calculated Zs (ie do an R1+R2 reading) in the absence of a standard Zs reading.

Is there any issue with the differences between the two Ze readings? (the 2015 Ze reading seems quite low comparatively with the 2008 Ze reading)

This does also still leave the question about the low readings on the heating circuit insulation resistance (less than 1MΩ) so I'd be grateful if you would let me know "attention" this circuit might need, in your opinion?

Thanks guys, your help is much appreciated.