BS7671 test and internal electric heating

[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.

 

[Leesparkykent]

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.

I think you are giving this spark a hard time lol.

 

[Soup]

I think you are giving this spark a hard time lol.

Haha :90:

Hope I don't have this much difficulty when the PAT Tester does his thing in a couple of days ;o)

 

[Leesparkykent]

Haha :90:

Hope I don't have this much difficulty when the PAT Tester does his thing in a couple of days ;o)

Not the same electrician isit? Haha :crazy:

 

[newtothis]

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

LOL I'm new to this - first thing I did was google the system the OP kindly provided at the outset.
The electrical installation cert for this system would be handy.
I've been taught as a tester you'd refer to previous test results as a way of monitoring changes, eg like deteriorating IR results. ETC
Seems like the OP didn't provide this info to the spark but has produced it after the inspection to question the current inspection.
Just giving my opinion, don't mean any harm to anyone.
I'm grateful to the OP cos a few years down the line when I'm competent to carry out EICRs I will hang up the phone if anyone mentions this system. LOL

 

[HappyHippyDad]

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.

With regards the Ze reading differences, that is quite a difference! I have only been in business for 3 years but have not come across a Ze of 0.04Ω before, it would be interesting to know if the more experienced electricians on the site have? Even if they have then that doesn't account for the difference. Unless your area has had some electrical work done locally I may be inclined to think he has measured the Ze without disconnecting the main bonding (It would be silly to go into detail about what this actually means Soup, but you could ask him if he did).

Also, those Insulation resistance readings are far too low and you should definitely have an electrician back to check them as if they are correct then there is a fault on the circuit somewhere. I dont want to go into detail about what they mean as it just gets too confusing, also it is very difficult to say more withour being there. Your most recent electrician should have looked at this previous report.

I feel 2 hours is nowhere near enough time to do a proper electrical report on a house, unless your home is a one bedroom flat then perhaps you could justify it if it just has perhaps 3 circuit breakers in the consumer unit (fuse box). Also 2 hours could be justified if before hand you had agreed on a very specific report that was only checking certain things, but in general a report takes at least half a day (4 hours) for a 3 bed semi (I take 3/4 day for a 3 bed semi and charge £150).

I think you are giving this spark a hard time lol.

Thats what I have been thinking Lee up until Soups above 2 posts, but 2 hours to complete a full report? How long do you take Lee and be honest?

 

[Leesparkykent]

With regards the Ze reading differences, that is quite a difference! I have only been in business for 3 years but have not come across a Ze of 0.04Ω before, it would be interesting to know if the more experienced electricians on the site have? Even if they have then that doesn't account for the difference. Unless your area has had some electrical work done locally I may be inclined to think he has measured the Ze without disconnecting the main bonding (It would be silly to go into detail about what this actually means Soup, but you could ask him if he did).

Also, those Insulation resistance readings are far too low and you should definitely have an electrician back to check them as if they are correct then there is a fault on the circuit somewhere. I dont want to go into detail about what they mean as it just gets too confusing, also it is very difficult to say more withour being there. Your most recent electrician should have looked at this previous report.

I feel 2 hours is nowhere near enough time to do a proper electrical report on a house, unless your home is a one bedroom flat then perhaps you could justify it if it just has perhaps 3 circuit breakers in the consumer unit (fuse box). Also 2 hours could be justified if before hand you had agreed on a very specific report that was only checking certain things, but in general a report takes at least half a day (4 hours) for a 3 bed semi (I take 3/4 day for a 3 bed semi and charge £150).



Thats what I have been thinking Lee up until Soups above 2 posts, but 2 hours to complete a full report? How long do you take Lee and be honest?

I price it at 1/2-40 mins a circuit depending on a quick visual. TBH I hate doing EICRs....but if I do them they are done properly but most of the landlords round my way go for the cheapest quote which isn't me.

 

[Soup]

LOL I'm new to this - first thing I did was google the system the OP kindly provided at the outset.
The electrical installation cert for this system would be handy.
I've been taught as a tester you'd refer to previous test results as a way of monitoring changes, eg like deteriorating IR results. ETC
Seems like the OP didn't provide this info to the spark but has produced it after the inspection to question the current inspection.
Just giving my opinion, don't mean any harm to anyone.
I'm grateful to the OP cos a few years down the line when I'm competent to carry out EICRs I will hang up the phone if anyone mentions this system. LOL

Thanks for this. I've tried to get details of the system already from the management company, freeholder/freeholder's agent and the maker of the system but to no avail.

Being honest here, it completely slipped my mind that I had the 2008 inspection done until I got into the argument with the electrician about the 2015 inspection - it was fortuitous that I managed to find a copy of the report after such a long period of time! So I didn't mean to try and catch him out or anything.

With regards the Ze reading differences, that is quite a difference! I have only been in business for 3 years but have not come across a Ze of 0.04Ω before, it would be interesting to know if the more experienced electricians on the site have? Even if they have then that doesn't account for the difference. Unless your area has had some electrical work done locally I may be inclined to think he has measured the Ze without disconnecting the main bonding (It would be silly to go into detail about what this actually means Soup, but you could ask him if he did).

OK I'll ask him that and see what he says!

Also, those Insulation resistance readings are far too low and you should definitely have an electrician back to check them as if they are correct then there is a fault on the circuit somewhere. I dont want to go into detail about what they mean as it just gets too confusing, also it is very difficult to say more withour being there. Your most recent electrician should have looked at this previous report.

As noted above, he didn't have sight of this old report but that's only because he wasn't aware of it (and I wasn't reminded of it until after the inspection).

I'll ask him again about the insulation resistance although I think it'll annoy him and he'll just refer back to the fact there was no power in the circuit and/or there are pin timers in the circuit, preventing a proper test!

I feel 2 hours is nowhere near enough time to do a proper electrical report on a house, unless your home is a one bedroom flat then perhaps you could justify it if it just has perhaps 3 circuit breakers in the consumer unit (fuse box). Also 2 hours could be justified if before hand you had agreed on a very specific report that was only checking certain things, but in general a report takes at least half a day (4 hours) for a 3 bed semi (I take 3/4 day for a 3 bed semi and charge £150).

To be fair, the 2 hours was just an estimate based on his hourly rate for other non-electrical work (£45/hour) so just a guess on my part. My property is a 2-bed flat so maybe that would be OK in terms of time spent in this instance. The fact he didn't measure certain things like R1+R2/R2 etc might be where he "saved time". Nice to know my continual questions don't seem to be so over the top now though :shades_smile:

 

[newtothis]

[FONT=&quot]Wishing every success with your venture Soup – there seems to be endless red-tape with absolutely everything these days. [/FONT]

 

[YoungScud]

I'll ask him again about the insulation resistance although I think it'll annoy him and he'll just refer back to the fact there was no power in the circuit and/or there are pin timers in the circuit, preventing a proper test!

Sorry to leap in late, but I've read this whole thread and I'm puzzled about something. Why would a lack of power affect insulation resistance tests? They have to be done with the power off. Zs testing can be done by measurement or calculation, meaning that, if you do a measured Ze test, you can calculate by adding R1 and R2, or you can measure Zs wit the power on. However IR testing is definitively a dead test.

 

[DuaneMHunt1976]

Would doing a Ze test with all the EARTHS in give you a real Dam Low 0.04Ohms value, apose to the 0.23 Ohms the last time

As YoungScud (so wanted to type in YoungStud then) said IR is a DEAD test, so No power Great, Zs a Live Test other wise its the R1+R2+Ze=Zs with no Power would be yes.