Basic questions

[melodymwah]

hi, im a student, and struggling with some questions that i cannot find an answer to:

1. If on filling in an eic and there is no info on the main service fuse (type/rating what should you do?

2. If main tails are not 25mm do you HAVE to upgrade them before carrying out any work?

3. Similiarily if main earth is not 16mm and main bond is not 10mm MUST this be upgraded first before carrying out any work

4. Also how would you split tails into a henley block?

5. How comes to run a seperate circuit for a 400w fridge, would you use a 20a radial when fridge only needs 2a

 

[randyrat]

1. Pull it and have a look
2. No, but recommend to client
3. No, but recommend to client
4. Two in, Four out
5. Fridges cause nuisance RCD trip, so are run on seperate labelled circuit outwith RCD protection

 

[mrloy99]

1. Pull it and have a look
2. No, but recommend to client
3. No, but recommend to client
4. Two in, Four out
5. Fridges cause nuisance RCD trip, so are run on seperate labelled circuit outwith RCD protection

I think I would dispute your no 5 claim that fridges cause rcd trip.The reason they tend to be on their own circuit would be that if another part of the circuit caused the trip,that the fridges contents aren't ruined. Washing machines are more likely to cause rcd trip due to capacitance causing inbalance.

 

[randyrat]

Always happy to bow to knowledge......the question was why would a seperate circuit be run for a fridge....which is why I answered as I did...although I do agree with your comment also.

 

[Spudnik]

3 should be uprated if any reasonably major work is done, i.e EIC issued. Also depends on the supply type as TT doesnt generally need 16 & 10.

All depends on the client tho.

 

[mrloy99]

Always happy to bow to knowledge......the question was why would a seperate circuit be run for a fridge....which is why I answered as I did...although I do agree with your comment also.

Don't get away with much in THESE parts matey.
Back to OP.The 2amp question-someone could perhaps move in to your house at a later date,and plug in a higher rated appliance.Radial circuits wired in 2.5mm are normally protected at 16amp OR 20 amp.The length of your radial circuit as well as load could determine your selection of circuit breaker,and don't forget if in uk you will also have a fuse in your plugtop suitably rated to your appliance.

 

[melodymwah]

ah, soif for example you were replaceing a consumer unit, but not increasing the load, and the customer refuses to pay for tails and earthing upgrade you woulkd replace the db {providing it is still safe} but record the tails and earthin as departures on eic as client refused them?

 

[Spudnik]

ah, soif for example you were replaceing a consumer unit, but not increasing the load, and the customer refuses to pay for tails and earthing upgrade you woulkd replace the db {providing it is still safe} but record the tails and earthin as departures on eic as client refused them?

I would look at this before quoting and then include it in the price if it needs upgrading.

 

[melodymwah]

but is it a this must be done full stop or only if neccesary, still getting various responses

 

[GT1]

Table 54.7 of BS7671:
minimum csa of protective conductor in relation to csa of line conductor where line conductor "s" 16mm<s<35mm: the table gives 16mm for protective conductors of same material.
There is an alternate formula at 543.1.3 but other factors need to be known.


As far as the bonding conductor sizes are concerned.
Table 54.8 under 544.1.1 (assuming PME)
The main bonding conductor for supply neutral conductors up to 35mm shall be 10mm

You are of course allowed to deviate away from 7671, however you will have to CERTIFY on the EIC that the deviation exceeds the regs and is safer the way you have done it.

 

[kermit1202]

ah, soif for example you were replaceing a consumer unit, but not increasing the load, and the customer refuses to pay for tails and earthing upgrade you woulkd replace the db {providing it is still safe} but record the tails and earthin as departures on eic as client refused them?

if the earthing and bonding are not up to standard, they should be upgraded or the consumer unit should not changed.

 

[Guest123]

Hey all.

Take a look at this guide, published by - The Electrical Safety Council (E.S.C)

http://esc.org.uk/pdfs/business-and-community/electrical-industry/BPG1_08.pdf

Page 7 concerns changing of consumer units.

Cheers.

 

[bahco]

nice link lenny

 

[GT1]

wow....
im having a few copies of that for the van..!!