Board Change

[MBEINST]

If the circuits are electrically sound and all tested correctly and haven't had alterations incorrectly installed , then as far as a consumer unit replacement goes the installation is compliant , the only note you can make is recommendations and advise the customer of them , both before work starts and on the installation cert..

This is what I thought and was looking for re-assurance which was provided thanks to telectix.

I am not comfortable at the thought of Mum ironing in the kitchen whilst making a brew, washing machine loaded and running perhaps dishwasher too. Daughter in her bedroom (heated by a portable radiator) using her hairdryer, Son gaming in his bedroom (Also heated by a portable radiator). Dad down the pub doing what most blokes should be doing whilst the brood are wasting his hard earned!

All on a 32A breaker.

 

[MBEINST]

20 double sockets can only pull what the MCB allows.

Obviously and they will be RCBO's

 

[R G]

This is what I thought and was looking for re-assurance which was provided thanks to telectix.

I am not comfortable at the thought of Mum ironing in the kitchen whilst making a brew, washing machine loaded and running perhaps dishwasher too. Daughter in her bedroom (heated by a portable radiator) using her hairdryer, Son gaming in his bedroom (Also heated by a portable radiator). Dad down the pub doing what most blokes should be doing whilst the brood are wasting his hard earned!

Then go ahead and do what you think is right in your eyes , Your obviously in a position to recommend and work to be carried out if its a relative your working for..IMHO...

 

[davesparks]

Nuisance tripping.

Best practice would be that the lights would be on separate circuits not dependent on the same breaker.

Kitchen sockets would have their own circuit and so would upstairs and downstairs.

20 double socket outlets could potentially pull 520A, even allowing for diversity this would be an issue.

Perhaps if I am wrong someone could justify why this arrangement would comply with current regs?

20 double sockets fully loaded to their rated current would total 400A not 560A, BS1363 twin socket is rated to 20A.

If you go round that house and switch on every single thing with a plug on it and then log the total current draw over an hour and then plot it on a graph against the tripping curve of a 32A MCB then you will see exactly how overloaded that circuit is not!

The average house (showers excepted) won't see more than 20A through its tails for any sustained period.

 

[MBEINST]

20 double sockets fully loaded to their rated current would total 400A not 560A, BS1363 twin socket is rated to 20A.

Not sure where the 560A came into it but in my house my sockets can take a plug fitted with a 13A fuse. My kettle is rated at 3000W.

Now in theory if I plugged 40 of these kettles into the circuit the demand would be:

40 X 13 = 520.

Obviously the breaker would trip.


Thanks to all for your input.

I am now officially bored with this thread.

 

[davesparks]

This is what I thought and was looking for re-assurance which was provided thanks to telectix.

I am not comfortable at the thought of Mum ironing in the kitchen whilst making a brew, washing machine loaded and running perhaps dishwasher too. Daughter in her bedroom (heated by a portable radiator) using her hairdryer, Son gaming in his bedroom (Also heated by a portable radiator). Dad down the pub doing what most blokes should be doing whilst the brood are wasting his hard earned!

All on a 32A breaker.

lets see now, assuming every item is switched on simultaneously and all start at full load:

Electric iron - 1.2KW
Kettle - 3KW
W/M - 1KW
D/W - 1KW
Heater 1 - 2KW
Hairdryer- 1.2KW
Heater 2 - 2KW
Playstation - 0.1KW

Total connected load - 11.3KW = 47A

Load at instant of switch on - 47A
Kettle boils within 5 minutes, load reduces to 34.58A
Daughter takes 10 minutes to dry her hair, load reduces to 25.41A
Obviously the other loads will be cycling according to their thermostatic controls/operating cycles so these loads will never really be reached.

Look in your regs book on page 301 and compare this to the tripping times of the 32A MCB, you will find that the 32A MCB allows 50A to flow for just over 15 minutes. All of our cable standards and ratings take account of this and the regs even allow for short duration overloads.

Now once again, where is the problem?

 

[davesparks]

20 double sockets fully loaded to their rated current would total 400A not 560A, BS1363 twin socket is rated to 20A.

Not sure where the 560A came into it but in my house my sockets can take a plug fitted with a 13A fuse. My kettle is rated at 3000W.

Now in theory if I plugged 40 of these kettles into the circuit the demand would be:

40 X 13 = 520.

Obviously the breaker would trip.


Thanks to all for your input.

I am now officially bored with this thread.

Take another look, BS 1363 specifies that a twin socket be capable of taking a 20A load, no more. Specifically they must be able to take a 13A load in one side and a 7A load in the other. Some manufacturers rate their twin sockets to 26A but you cannot assume this is the case. So if 2 x 13A loads are plugged in to a twin socket the socket is overloaded by 6A.

 

[Geordie Spark]

Nuisance tripping.

Best practice would be that the lights would be on separate circuits not dependent on the same breaker.

Kitchen sockets would have their own circuit and so would upstairs and downstairs.

20 double socket outlets could potentially pull 520A, even allowing for diversity this would be an issue.

Perhaps if I am wrong someone could justify why this arrangement would comply with current regs?

As long as the work that YOU do complies to current regs, then it doesn't matter what edition of the regs the existing installation complies to AS LONG AS IT CHECKS-OUT AS "SAFE".

 

[Pete999]

520 Amps potential, 32 Amp breaker don't quite add up mate

 

[Megavolt]

You are looking to deep into this. I like how thorough you have been but as said you will come across this proberly hundreds of time in future and as long as it tests out ok just reconect into CU get paid move on.

 

[Megavolt]

PS

Not ideal I know put lost count how many times I have come across a large flat CU fed via a 32 amp Mcb that has never tripped.

 

[UNG]

Nuisance tripping.

Best practice would be that the lights would be on separate circuits not dependent on the same breaker.

Kitchen sockets would have their own circuit and so would upstairs and downstairs.

20 double socket outlets could potentially pull 520A, even allowing for diversity this would be an issue.

Perhaps if I am wrong someone could justify why this arrangement would comply with current regs?

The same way it complied with the regs in force when it was originally installed, since it was installed how many times has this circuit come close to drawing 520A I bet it very rarely draws more than 5% of that

This is what I thought and was looking for re-assurance which was provided thanks to telectix.

I am not comfortable at the thought of Mum ironing in the kitchen whilst making a brew, washing machine loaded and running perhaps dishwasher too. Daughter in her bedroom (heated by a portable radiator) using her hairdryer, Son gaming in his bedroom (Also heated by a portable radiator). Dad down the pub doing what most blokes should be doing whilst the brood are wasting his hard earned!

You paint a very good picture of appliance use but does it ever happen the way you describe

All on a 32A breaker.

So what is the existing over current protection a rusty nail? or is it a piece of 30A fuse wire in a carrier that shows no signs of it ever blowing

20 double sockets fully loaded to their rated current would total 400A not 560A, BS1363 twin socket is rated to 20A.

Not sure where the 560A came into it but in my house my sockets can take a plug fitted with a 13A fuse. My kettle is rated at 3000W.

Now in theory if I plugged 40 of these kettles into the circuit the demand would be:

40 X 13 = 520.

Obviously the breaker would trip.


Thanks to all for your input.

I am now officially bored with this thread.

This comment says a lot about you and come to think about so does this thread


Too many on here take on a simple job and seem to find / create problems that don't and never did exist

 

[Guest77]

Hi Guys,


Just been to quote for a consumer unit change.


Bonding is good, Zs is good, Seven circuits:


Shower, no problems foreseen.


Cooker, no problems foreseen.


All Sockets main house on one Ring, I am not comfortable with one 32A RCBO protecting sockets in kitchen, upstairs and downstairs (20 in total). I have advised that at least the kitchen needs to be on its own circuit.


Garage conversion separate Ring, no problems foreseen.


All lights main house on one radial (7 in total), obviously not upto current regs but not an issue in terms of load.


Garage conversion lights, no problems foreseen.


Alarm same circuit, no problems foreseen.


Unfortunately couple don’t want to pay for the extra work or disturb the decorative state. Replacing the current re-wirable bakerlite board with a fully populated RCBO board would obviously make the whole installation much safer.


Would I be wrong to connect the main house ring to the new board as it stands?


Comments/advice would be much appreciated.


Cheers

Why? I have 30 on one ring in my house and it is on a board with no RCD protection, works lovely, I bet I don't pull 15 amps, diversity works as well now as it did before the IET decided to frighten us all with figures most find confusing. Obviously the chance of nusience tripping is evident, and I do understand your point there.

 

[MBEINST]

This comment says a lot about you and come to think about so does this thread


Too many on here take on a simple job and seem to find / create problems that don't and never did exist

If being thorough creates doubts, and I seek re-assurance I'll carry on.

Ask a question and be a fool for a minute, don't ask and remain a fool permanently!

Over caution never killed anyone!

 

[Octopus]

I would recommend reading this thoroughly:

http://www.select.org.uk/downloads/ESC Best Practice Guide No. 6 - Issue 2.pdf