Board Change

[MBEINST]

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

 

[telectrix]

just do the CU. it's your work that needs to be to current regs, not existing installation, as long as circuits are safe to connect to new CU.

 

[davesparks]

What is wrong with the existing ring and lighting circuits?

 

[MBEINST]

just do the CU. it's your work that needs to be to current regs, not existing installation, as long as circuits are safe to connect to new CU.

Thanks telectix, thats the assurance I was looking for.

Cheers

 

[MBEINST]

What is wrong with the existing ring and lighting circuits?

Electrically nothing that I have found but obviously not done full set of tests yet. They do not conform to current regs but may have done when installed.

 

[davesparks]

What about the existing circuits does not conform to current regs?

 

[MBEINST]

What about the existing circuits does not conform to current regs?

Dave, I'm sure you know the answer to this or would you consider doing an installation in this manner nowadays.

 

[R G]

Yes , what doesn't conform , please explain,,,

 

[Octopus]

Dave, I'm sure you know the answer to this or would you consider doing an installation in this manner nowadays.

There are millions of installations in the UK that don't meet the current regs or design layouts - BUT that doesn't mean they are unsafe...........

 

[Octopus]

Yes , what doesn't conform , please explain,,,

They don't "conform" to best practice in 2014!

 

[R G]

They don't "conform" to best practice in 2014!

We all know you wouldn't install it that way , but this is existing circuits...

 

[MBEINST]

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?

 

[R G]

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..

 

[Octopus]

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?

then fit a RCBO board

 

[telectrix]

20 double sockets can only pull what the MCB allows.

 

[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.