UK Niceic Assesment

[banny07]

Hi all. My first niceic assesment for joining is coming soon. I want to show my friends house where I installed new fuse board and installed new smoke alarm circuit. My question is what should I fill in sesign and construction section? should I leave it blank?
The house have no cooker or shower circuit only three final circuits which have 3, 5 and 7 double sockets as well as two lighting circuits with 7 and 8 lighting points .Third circuit has only three smoke/heat alarms. Maximum demand will be around 26Amps?
Any advice will be very helpful. Thanks in advance

 

[timhoward]

I've had a quick look through, you might want to take your name address and phone number off it, as well as the customers and post it again. A few comments:
Extent: I'd say "consumer unit" not fuse board, and maybe say "additional" smoke alarm circuit to clarify that's the addition.
Section 3.1 - very common mistake, RCD for fault protection should not be ticked on a TN system assuming all Zs values are within limits. ADS is providing fault protection, the RCBO's are providing additional protection.

Is the wiring all new colours? The IR results suggest older wiring, just wondered if it does need two colours sticker which you have as N/A in section 7.10

Add the serial number of your tester on page 5 in the finished version, so it can be proved it was within calibration if required.
The Zs at DB at top of page 5 should presumably be 0.2 not 20 ohms
The Zs of circuit 6 is significantly less than the R1+R2....which looks a little bit interesting. Any bonding or parallel paths you are aware of?
Circuit 7 the same to a lesser extent. (I'm wondering if there is some cpc link between 6 and 7 on the stairs lighting....random possible cause)

I don't like that the RCD column on that form doesn't specify whether x1 or x5 trip current.

Sorry for bit of a list! I haven't listed the many things you got right so don't be discouraged!

EDIT - what did you have in mind for section 6.1, class II equipment?

 

[banny07]

I've had a quick look through, you might want to take your name address and phone number off it, as well as the customers and post it again. A few comments:
Extent: I'd say "consumer unit" not fuse board, and maybe say "additional" smoke alarm circuit to clarify that's the addition.
Section 3.1 - very common mistake, RCD for fault protection should not be ticked on a TN system assuming all Zs values are within limits. ADS is providing fault protection, the RCBO's are providing additional protection.

Is the wiring all new colours? The IR results suggest older wiring, just wondered if it does need two colours sticker which you have as N/A in section 7.10

Add the serial number of your tester on page 5 in the finished version, so it can be proved it was within calibration if required.
The Zs at DB at top of page 5 should presumably be 0.2 not 20 ohms
The Zs of circuit 6 is significantly less than the R1+R2....which looks a little bit interesting. Any bonding or parallel paths you are aware of?
Circuit 7 the same to a lesser extent. (I'm wondering if there is some cpc link between 6 and 7 on the stairs lighting....random possible cause)

I don't like that the RCD column on that form doesn't specify whether x1 or x5 trip current.

Sorry for bit of a list! I haven't listed the many things you got right so don't be discouraged!

EDIT - what did you have in mind for section 6.1, class II equipment?

Thanks a lot! Wiring is of new coloursbut abot 10-15 years old. I will test these lighting circuit again with lamps removed. You are right about cpc link as there is 2 gang stair light switch (Two way),Is there a way to avoid this? Zs at DB also 0.21 as you correctly pointed out! about class ll equipment I was thinking hair dryer,electric beard trimmers etc, please advise me on that. I will keep in mind about your advice about section 3.1. What is your opinon on live to E insulation and SPD?
I will upload revised pdf file again tomorrow. Address and phone number will be removed. Thanks again for your valueable advice.

 

[westward10]

I have deleted your pdf but feel free to repost with the details omitted. For a dwelling Class II will never be applicable as it is not deemed a suitable measure of protection for such an installation as it needs to be monitored.

 

[timhoward]

What is your opinon on live to E insulation

For 10-15 year old wiring the IR on the sockets (while a pass) is low in my view. If you have time it might be worth splitting the ring and and testing each leg - if one half is much higher then maybe hunt down the reason for the low reading by continuing to divide and test. This can be time consuming and might not be viable now.

and SPD?

I'm assuming it's one that connects to the bus-bar - I wouldn't worry about it. It can be tested using IR tests but I haven't seen this happen much in reality.

about class ll equipment I was thinking hair dryer,electric beard trimmers etc, please advise me on that.

This is more about a means of protection for the fixed wiring - not applicable to a dwelling according to regs. You aren't concerned with anything plugged into the fixed wiring for purposes of the report.

You are right about cpc link as there is 2 gang stair light switch (Two way),Is there a way to avoid this?

This is an interesting one that it would be good to get other people's opinions on too. Generally it's easiest from a testing and future work point of view if cpc on circuits are completely self contained. This isn't an absolutely requirement though, plenty of industrials use metal trunking as cpc for more than one thing.
Bottom line is that the back boxes need earthing if metal, and the cables need a cpc connected at least one end to protect them along their length.
My gut reaction would be to connect the back boxes to the respective cpc (upstairs to up lighting, downstairs to down lighting), and choc block the cpc at one end of 3 core, thus avoiding interconnecting the circuits.
(Alternatively circumvent anyone finding this curiosity and write down Zs as Ze+(R1+R2) by calculation for these circuits. Zs can be legitimately lower than R1+R2, for example a boiler connected to bonded pipes can cause this. )

 

[banny07]

For 10-15 year old wiring the IR on the sockets (while a pass) is low in my view. If you have time it might be worth splitting the ring and and testing each leg - if one half is much higher then maybe hunt down the reason for the low reading by continuing to divide and test. This can be time consuming and might not be viable now.

Thanks a lot! Some how if I Test insulation between live L to N , L to E or N to E it goes over 150 mega ohm but extremely low when tested between LIVE-LIVE joine togather to E. Don't know why.Thanks again

 

[timhoward]

Interesting. Very random idea - did you put the L and N back in the RCBO during that test and does the RCBO have a functional earth wire that remained connected?

 

[westward10]

What is extremely low?

 

[timhoward]

What is extremely low?

On the report (that isn't back up yet) I think it was 5 Mohms for one circuit and 7 Mohms for other.
I know they both pass.

 

[banny07]

Interesting. Very random idea - did you put the L and N back in the RCBO during that test and does the RCBO have a functional earth wire that remained connected?

I used connecting block to join L +E together, cpc's were left connected in the earthing terminal in the cosumer unit. Thanks

 

[banny07]

What is extremely low?

Insulation resistance.It will pass but as Timhoward suggested I wanted to investigate. Thanks

 

[banny07]

does the RCBO have a functional earth wire that remained connected?

These RCBO don't have functional earth. Thanks

 

[banny07]

On the report (that isn't back up yet) I think it was 5 Mohms for one circuit and 7 Mohms for other.
I know they both pass.

Here is updated installation certificate guys! Please have a look and point out any area I need to improve.Thanks again.

 

[timhoward]

I see I completely mis-remembered and the IR was 18Mohms. Unless you have time on your hands I'd leave that.
The main thing with this (and other comments) was you having a comment ready for an assessor picking it up. I've known assessors not give an IEC a 2nd glance, and a different one spent 30 minutes talking about it! Luck of the draw really....

 

[banny07]

I see I completely mis-remembered and the IR was 18Mohms. Unless you have time on your hands I'd leave that.
The main thing with this (and other comments) was you having a comment ready for an assessor picking it up. I've known assessors not give an IEC a 2nd glance, and a different one spent 30 minutes talking about it! Luck of the draw really....

I had an email from assessor to email him IEC. Please advise if it is good enough to emailed to him. Could you please information why insulation reader is lesser when testing between Live-Earth than live- live?Thanks

 

[catdog1121]

I had an email from assessor to email him IEC. Please advise if it is good enough to emailed to him. Could you please information why insulation reader is lesser when testing between Live-Earth than live- live?Thanks

Looks ok.. My only comments and they are very minor.

1. Under main switch, put N/A in all empty boxes so it cannot be modified..
2. In your insulation resistance tests you have a variety of greater than values, generally you put greater than when you reach the limit of your tester, think some older MFT were 299, hence you will often see >299, if its a modern one that goes upto 999 then put the reading you have not >200 as its a record that will help future electricians so being more accurate is better.
3. Under test instruments details, I would put the make and model of the MFT not just "MFT"
4. This is an EIC not EICR so you should not have general limitations, but if there are circuits where you cannot do testing say Live to neutral insulation resistance, then these circuits and reasons should be stated in details of circuits vulnerable to damage when testing. You should really be doing L-N on an EIC unless it is not feasible, and if it is not feasible then write why. The only circuit you identified is smokes although thats the only circuit you have actually fully tested so why is it identified as a circuit that could be damaged by testing? Sockets you should unplug everything and isolate any FCU's, if they have multiple usb sockets or there are sockets with things plugged in that you cannot reach without moving heavy furniture risking damage then thats fair enough but put that. Again with lighting you should remove all lamps and do L-N testing, if they have a load of downlights with integrated LED's then again fair enough its not feasible to disconnect them but put that.

Not doing L-N insulation resistance testing he might pick you up on it as it stands out that you have not put reasons for not doing it and looks like you have just avoided it which is fine if its a limitation on an EICR but not for an EIC.