Testing

[hous1]

Hi
could someone help me as i have just completed my first installation on a two storey extension and i added a extraction fan a shaver socket and 1 additional light to an existing lighting circuit in a bathroom and then added two lights for the additional rooms of the extension to the same 6 amp mcb on new wiring all of which add up to 4amp,my question is should i test the existing lighting circuit which i added to as well as the new lighting circuit which is new because they are coming of the same mcb.

 

[DaveyD]

No, with respect you should have checked on before design not after installation.

 

[GLENNSPARK]

yep....need to check FIRST that any work you do or any additions to an existing circuit will not be detremental to the existing circuit/install.....such as ensuring disconnection times will still be met and existing cable/s will not be overloaded etc.....

 

[hous1]

Hi
thanks,ihave actually checked both circuits but on the installation forms do i only put the readings of the new circuit as i only added to the existing and that would have been tested for the correct breaker and insulation resistance previously,or is it a case of as soon as you add to an existing circuit you record your highest reading of the circuits on that breaker.

 

[SimpleSimon]

I would be doing a MWC for the addition of the new circuit and a EIC for the extension. Both are than covered.

Sent from my GT-I9100 using Tapatalk

 

[ipf]

Same mcb, same circuit, surely.

 

[telectrix]

it's an alteration to a circuit, so MEWIC , and record the highest readings of R1+R2 and Zs,

 

[Hawk81]

And test Rcd times

 

[ringer]

The circuit starts at the MCB (or RCBO), so test results must be recorded for all cables coming from that mcb. If you have two radials, or a ring and a radial, for example, off that mcb then you need to test it all. It is no good saying you have only altered/added one of the radials and then only supplying test results for that one radial. If a higher Zs or lower IR exists on the part of the circuit you did not touch, you still need to record it.

 

[hous1]

Thankyou,i'm now clear on that,i'm looking for certificates for installation and commissioning of a fire detection system form number FHM3 (B-F) i have all other certificates but cant find these,any suggestions.

 

[ringer]

The basic package of EasyCert has this, I believe. Costs about £40 but I can not vouch for how good it is as have not seen/used it myself. You do get all other certs with it as well for that price.

 

[EastAnglian]

The circuit starts at the MCB (or RCBO), so test results must be recorded for all cables coming from that mcb. If you have two radials, or a ring and a radial, for example, off that mcb then you need to test it all. It is no good saying you have only altered/added one of the radials and then only supplying test results for that one radial. If a higher Zs or lower IR exists on the part of the circuit you did not touch, you still need to record it.

Pragmatically it is sensible to do this because it is always a good idea to be looking for latent defects and other issues which may affect the owner of the installation. If nothing else, its good business!

However, Regulation 633.1 is quite specific on what is required formally:

"The requirements of Sections 631 and 632 for the issue of a EIC or a MEWC shall apply to all the work of the additions or alterations".

In other words, it is ONLY what you add that requires testing.

 

[GLENNSPARK]

Pragmatically it is sensible to do this because it is always a good idea to be looking for latent defects and other issues which may affect the owner of the installation. If nothing else, its good business!

However, Regulation 633.1 is quite specific on what is required formally:

"The requirements of Sections 631 and 632 for the issue of a EIC or a MEWC shall apply to all the work of the additions or alterations".

In other words, it is ONLY what you add that requires testing.

yes but lets say its a lighting circuit thats been extended/added to then.....so you do a Zs on it.....will be typically at the furthest point where you can expect to get a highest reading yes....but you are still testing the integrety of the existing circuit yes....what was there before......

 

[jase]

i would do a minor works for the fan and shaver point as you have only added/altered an existing circuit and i would do a EIC for the new circuit back to the board, both circuits are tested just recorded diferently, on both certificates you write down the extent to which the cert covers.

 

[EastAnglian]

GLENSPARK - yes of course, Zs is a test of the whole circuit, no problem with that!

However, the figures for R1+R2 and IR as entered onto the MEWC are those for the extension to the circuit only ... tested before you connect then in because the scope of work is only the addition.

I will often test end to end as I'm sure you do because it allows me to be more confident that the customer is going to be happy with my work, but that wasn't the question!

 

[tigerpaul]

I believe that you take ownership of the entire circuit when you add to it. Therefore you need to test the circuit as a whole.

If a lighting circuit for example has IR readings of 50meg ohms but all your new cabling tests out at >299 meg ohms, you still need to record the result as 50.

 

[EastAnglian]

Is this what you actually do? e.g. you have a "simple" 1 hour job to add a smoke detector to a lighting circuit in a large house, do you actually take out all the light bulbs, turn on all the light switches, disconnect the cables in the distribution board and carry out 3 insulation tests L-N, L-CPC, N-CPC on the whole circuit?

I don't!

 

[tigerpaul]

If you work on a circuit, don't you want to know it is safe and compliant?
And remains so after you've gone...

 

[jase]

BS7671 part 3 assesment of general characteristics
although it may well not be part 3 now as i havent got BGB yet :behead:

 

[EastAnglian]

If you work on a circuit, don't you want to know it is safe and compliant?
And remains so after you've gone...

Yes, but the question was about what you record on the certificate!

I agree, there is a professional obligation to satisfy yourself through pre-installation checks and other tests that the installation is safe. In the example I used above if I did have doubts I might carry out an IR test between L+N joined together and CPC but I would record this in my notebook or on the job sheet, not on the certificate.

 

[tigerpaul]

Yes but if you issue a certificate showing a circuits details and results, it should reflect the whole circuit, not just the "new bit"

 

[EastAnglian]

No, Regulation 633.1 is quite clear on that.

 

[jase]

yes it states that all of the conditions of SECTIONS 631 and 632 shall apply to all the work of the addition or alteration, so if you read 631.3 which is in SECTION 631 it says an MWC may be provided for each circuit altered or extended.

the CIRCUIT i.e the whole thing

it doesnt say you can just test the new bit and to hell wether or not you have just connected up to an unsafe installation!!!!

 

[EastAnglian]

yes it states that all of the conditions of SECTIONS 631 and 632 shall apply to all the work of the addition or alteration, so if you read 631.3 which is in SECTION 631 it says an MWC may be provided for each circuit altered or extended.

the CIRCUIT i.e the whole thing

it doesnt say you can just test the new bit and to hell wether or not you have just connected up to an unsafe installation!!!!

Interesting, and I understand the point you are making. However, using the same example, lets say I connect a smoke detector to a lamp on a lighting circuit, but not to the lamp at the end of the radial circuit. What do I measure to enter a value for R1+R2 on the MWC?