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.

 

[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!!

 

[voltage]

thanks for all your replies guys its a great forum with very knowlegable people and a great source of info. Im not sure what reputation domestic installers have but i want to be the best i can be in that field and try and do everything by the bible ( BRB ) even though i think in the real world sometimes i think compromise will have to come into play. Ive spent a small fortune on kit to make sure i have everything plus course fees etc im probably looking south at circa 3/3.5 grand. Im gonna see how my inspection goes but i would like to do the inspection and testing course the level 2 one to start with 2392-10 is this qual sufficient enough for me as a domestic installer dealing only with single phase or will i need to do the level 3 2391-10 ? what would you guys suggest ?

 

[B6 7BU]

Are you planning on calculating or measuring your Zs?

What does the Law say?

 

[Johnny-G]

As far as I'm aware the Law has no opinion on the matter.

 

[chiplard]

I will always calculate Zs.

This way you have a measured Ze and a measured (R1+R2) - in theory the highest possible value for the circuit to ensure it meets the required value for the protective device.

By measurement you will include all other parallel paths that may in future be removed.

Not in any book you will read but it satisfies me.

 

[steveautomation]

Im gonna see how my inspection goes but i would like to do the inspection and testing course the level 2 one to start with 2392-10 is this qual sufficient enough for me as a domestic installer dealing only with single phase or will i need to do the level 3 2391-10 ? what would you guys suggest ?

depends what you want to get out of it in the end.

How experienced are you at test and inspection?

If your not that experienced i would suggest doing the 2392-10 course to start as it covers all of initial verification and i have found it to be very helpful myself, it covers single phase domestic / small commercial type installations and goes through all the inspection, test and certification info.