continuity of radial circuits

[voltage]

Hi all

First off some info about me im early 30s :/ had to retrain so went back to college and undertook a domestic installers course and also the bs7671 17th edition which i passed with a healty 91% got all my certs etc.
I've now applied to the NICEIC to come out and inspect me on a major which will be a consumer unit change at my mum and dads house. The choice of consumer unit ive opted for is a MK dual RCD 17th edition board.

Regards to testing ive bought the NICEIC dvd on inspection and testing initial verification for domestic properties.

so i just want to run some things past you guys to see if im correct.


continuity of radial circuit protective conductors

I've safely isolated the supply and locked it off ive tested it with a martindale voltage indicator and proving unit to prove its dead.

the way i would use would be to dissconnect the gas and water bonding conductors so not to include them.

now say im testing the lighting circuit downstairs i would link the line and cpc from lighting circuit into connector block together set my megger on ohms for continuity and test switch line and cpc at each celling rose on the circuit with switch on then switch off to prove polarity. Iwould take the highest reading and this would be my R1 + R2 which goes on the cert ? is this way correct ?


Say im testing a shower circuit would i use the same procedure as above but instead of celling rose i test from consumer unit to 45amp double pole switch and at shower point aswell ? if someone could explain this one to me i would be very gratefull.

 

[Johnny-G]

When you remove the cpc from it's terminal in the cu there's no need to remove the bonding.
If they are existing circuits then just take the reading from the last fitting on the circuit, that applies to any radial whether lighting, shower, cooker etc.

 

[voltage]

thanks for the quick reply much appreciated. Could you tell me if the method i used to check the radail lighting circuit would be the same method to apply for the shower circuit ?

 

[ukpablo]

just test it to its furthest point, so test it at shower and confirm polarity by operating the switch, but sounds right to me. The reason u test at all light points in a cct is because u dont always know which is the furthest point, unless u have rewired the house and u would have taken a note of this for ur testing. GN3 explains this really well if u dont already have it.

 

[telectrix]

your method for R1+R2 looks good. shower is as you say. link Land cpc at CU and measure from load. but. 1. when you say megger, i assume you mean muti functin tester. 2. as your circuit is disconneced fron CU for testing, no need to disconnect water and gas bonds. 3 . also measure Rn+R2, tyo compare, but enter R1+R2 on test results.

 

[voltage]

yes sorry its a multifunction tester megger 1553 is what i have bought. Thanks for all the replies guys much appreciated.
So on a shower circuit at the consumer say 10mm cable link the 10mm live and 4mm earth together in connector block then test at the furthest point being the shower unit itself and test line and earth their ? correct ?

 

[Johnny-G]

Yes, if you can get the 10mm in a connector block

 

[V]

any chance you sending me a copy of that dvd ?

 

[voltage]

thank you very much yeah bit of a mission with 10mm

 

[Electricalserv]

How do you join the NICEIC with just one job?

 

[Johnny-G]

Are you planning on calculating or measuring your Zs?
As I know the DI courses generally only teach the calculation method whereas live measurement gives a more accurate reading of the complete circuit.

 

[voltage]

hey vince yeah i could get the mrs to copy it but not sure if it will be protected making it impossible to burn. But if i can then yeah u can have a copy no problem.

 

[voltage]

Yes johnny i plan on doing the full testing procedure as stated in bs7671 ill do the full tests including the live ones to measure pfc pssc etc

 

[telectrix]

use a block out of a henly block for the 10mm. and might be a better idea to go for elecsa or napit rather than niceic.

 

[Electricalserv]

How do you join the NICEIC with just the one job??????

When I rang them they said they wanted a list of 10 jobs, they will choose 5 of thyem jobs that they want to see. they also said you had to have been trading for 6months?????

 

[voltage]

How do you join the NICEIC with just one job?

When I rang them they said they wanted a list of 10 jobs, they will choose 5 of thyem jobs that they want to see. they also said you had to have been trading for 6months?????

They told me they want to see a major and a minor ive got a full cabin install i did for my dad for his office which involved runing swa fitting consumer unit ring main and lighting circuits etc the full monty but im gonna do the consumer unit change as my major then a minor not sure yet.

 

[rick.oshea]

Yep, you got it.....

you are measuring the resistance of the Line (R1) & CPC (R2) together by donig this.

It is at this point at which the resistance in the cable will be at its highest and when it is added to your Ze (external earth fault loop) then you get an overall resistance for that circuit (Zs) - this is then used and compared against the regs to ensure it is low enough to operate your safety device (fuse / mcb) using your ohms law. If you use the On-site guide, the figs published in here are 80% (rule of thumb) of the max found in the regs and therefore covers you for abient temperates, insulation & grouping.

 

[voltage]

use a block out of a henly block for the 10mm. and might be a better idea to go for elecsa or napit rather than niceic.

good idea

 

[Electricalserv]

They told me they want to see a major and a minor ive got a full cabin install i did for my dad for his office which involved runing swa fitting consumer unit ring main and lighting circuits etc the full monty but im gonna do the consumer unit change as my major then a minor not sure yet.

I'm really confused with the NICEIC then.... I was told I needed a list of 10 jobs and must have been trading for 6 months....

Can somebody clear this up??? Is there two parts to being NICEIC registered like Napit....I.e full and defined scopes?

 

[Johnny-G]

Dunno, have you asked NICEIC themselves?

 

[Electricalserv]

Dunno, have you asked NICEIC themselves?

Didn't know this was the case until now. Already payed Napit fees....

 

[V]

it seems customers ask for NIC but Napit etc are more trade friendly

 

[telectrix]

good idea

or just croc clip them.

 

[Guest123]

I'm really confused with the NICEIC then.... I was told I needed a list of 10 jobs and must have been trading for 6 months....

Can somebody clear this up??? Is there two parts to being NICEIC registered like Napit....I.e full and defined scopes?

Yes, the criteria you have been given is for Approved Contractor. The criteria of one major & one minor is for Domestic Installer only.

 

[Electricalserv]

Yes, the criteria you have been given is for Approved Contractor. The criteria of one major & one minor is for Domestic Installer only.

Thanks Lenny....What an absolute bummy would have loved to go NICEIC, if only their salesman would give out the correct info!!