It is getting to the point where I am ready to install my main CU so just checking for any "gotchas" that I have not considered.

The unit I am going for is this

https://www.toolstation.com/mk-metal...er-unit/p77771

It has most of the MCBs I need and what is not there I can cannibalise from my existing CU. The CU will be populated as follows;

100A main switch

Garage - MCB with a 10mm2 T&E feed for now a 40A MCB. This will not be RCD protected as it will be run through voids or surface mounted. The feed is probably a bit overkill for now but I am looking ahead to possible EV charging. The garage does have an RCD in the garage CU hopefully restricting any problems to it rather than tripping the main CU.

Alarm - 16A MCB with 2.5mm2 T&E this feeds a couple of sockets in the loft for the wall wart PSUs for the alarm again not RCD protected as cable will run through voids and surface wired.

RCD 1 80A

Kitchen - ring main with 2.5mm2 T&E with 32A MCB
Lights - This is the main light circuit 1.5mm2 T&E with a 6A MCB
Hob - This is a 3.7KW induction hob which I am hoping to utilise the existing 6mm2 feed to our existing hob just transposing it to its new location. I will probably use the existing 32A MCB although a 20A should do
Oven - 5.6KW Like the hob I will be using the existing 6mm2 feed and 32A MCB

RCD 2 63A

Ring main - This is the rest of the house (bungalow) 2.5mm2 T&E & 32A MCB
Kitchen lights - 1.5mm2 T&E & 6A MCB
Boiler - 2.5mm2 & 16A MCB just in case we ditch the combi and go back to a system boiler with a possible immersion heater.
Shower - This is a temporary circuit as the shower will be replaced with a digital type when the bathroom is done over so I will utilise the current 4mm2 T&E & 32A MCB till then.

This will leave me with 5 spare ways two might get used with a surge arrestor if I decide to implement the full 18th Regs. However, seeing as these are rather expensive and seem to be optional the jury is still out on that one. As far as I know I have never in my lifetime of ownership of houses ever suffered a lightening strike or a surge but having said that the gods of mayhem will have one lined up as soon as I get this CU installed😵..

Richard

On 25/08/2019 19:20, Tricky Dicky wrote:
It is getting to the point where I am ready to install my main CU so just checking for any "gotchas" that I have not considered.

The unit I am going for is this

https://www.toolstation.com/mk-metal...er-unit/p77771

It has most of the MCBs I need and what is not there I can cannibalise from my existing CU. The CU will be populated as follows;

100A main switch

Garage - MCB with a 10mm2 T&E feed for now a 40A MCB. This will not be RCD protected as it will be run through voids or surface mounted. The feed is probably a bit overkill for now but I am looking ahead to possible EV charging. The garage does have an RCD in the garage CU hopefully restricting any problems to it rather than tripping the main CU.

Alarm - 16A MCB with 2.5mm2 T&E this feeds a couple of sockets in the loft for the wall wart PSUs for the alarm again not RCD protected as cable will run through voids and surface wired.

RCD 1 80A

Kitchen - ring main with 2.5mm2 T&E with 32A MCB
Lights - This is the main light circuit 1.5mm2 T&E with a 6A MCB
Hob - This is a 3.7KW induction hob which I am hoping to utilise the existing 6mm2 feed to our existing hob just transposing it to its new location. I will probably use the existing 32A MCB although a 20A should do
Oven - 5.6KW Like the hob I will be using the existing 6mm2 feed and 32A MCB

RCD 2 63A

Ring main - This is the rest of the house (bungalow) 2.5mm2 T&E & 32A MCB
Kitchen lights - 1.5mm2 T&E & 6A MCB
Boiler - 2.5mm2 & 16A MCB just in case we ditch the combi and go back to a system boiler with a possible immersion heater.
Shower - This is a temporary circuit as the shower will be replaced with a digital type when the bathroom is done over so I will utilise the current 4mm2 T&E & 32A MCB till then.

This will leave me with 5 spare ways two might get used with a surge arrestor if I decide to implement the full 18th Regs. However, seeing as these are rather expensive and seem to be optional the jury is still out on that one. As far as I know I have never in my lifetime of ownership of houses ever suffered a lightening strike or a surge but having said that the gods of mayhem will have one lined up as soon as I get this CU installed😵.


Apart from waiting for dennis to tell you that 32A 2.5mm T&E final ring
circuits are the devils spunk I would say you are looking in good order
to install.

A load of ******** here for you to read and forget

https://professional-electrician.com...d-as-standard/


--
Adam

Tricky Dicky wrote :
RCD 1 80A

Kitchen - ring main with 2.5mm2 T&E with 32A MCB

Fridge and freezer on a none RCD circuit, to avoid food spoiling if
there is an RCD tripped in your absence?

On Sunday, 25 August 2019 19:59:32 UTC+1, ARW wrote:
A load of ******** here for you to read and forget
https://professional-electrician.com...d-as-standard/

"a relatively low-priced and widely available safety item"

low priced??

And isn't there a bit of a fire risk having something that goes pftttt in a consumer unit? In the top photo it's wired across the main switch and not even fused down

Owain

On 25/08/2019 21:50, wrote:
On Sunday, 25 August 2019 19:59:32 UTC+1, ARW wrote:
A load of ******** here for you to read and forget
https://professional-electrician.com...d-as-standard/

"a relatively low-priced and widely available safety item"

low priced??

And isn't there a bit of a fire risk having something that goes pftttt in a consumer unit? In the top photo it's wired across the main switch and not even fused down



like many (most?) such it comes built in fuses so needs no additional
overcurrent protection.

--
Robin
reply-to address is (intended to be) valid

On 25/08/2019 23:08, Robin wrote:
On 25/08/2019 21:50, wrote:
On Sunday, 25 August 2019 19:59:32 UTC+1, ARWÂ* wrote:
A load of ******** here for you to read and forget
https://professional-electrician.com...d-as-standard/

"a relatively low-priced and widely available safety item"

low priced??

And isn't there a bit of a fire risk having something that goes pftttt
in a consumer unit? In the top photo it's wired across the main switch
and not even fused down



like many (most?) such it comes built in fuses so needs no additional
overcurrent protection.


ahem...except on (still not sober) reflection & checking that seems to
be one that does require external overcurrent protection

--
Robin
reply-to address is (intended to be) valid

On 25/08/2019 20:38, Harry Bloomfield wrote:
Tricky Dicky wrote :
RCD 1 80A

Kitchen - ring main with 2.5mm2 T&E with 32A MCB

Fridge and freezer on a none RCD circuit, to avoid food spoiling if
there is an RCD tripped in your absence?

Tricky unless you use SWA or pay a lot of detail to the cable route.

On 25/08/2019 19:20, Tricky Dicky wrote:

snip

Shower - This is a temporary circuit as the shower will be replaced
with a digital type when the bathroom is done over so I will utilise
the current 4mm2 T&E & 32A MCB till then.

A 7kW shower is ok but many installs suggest 6mm. The voltage drop at
7kW will also limit the length of 4mm^2 cable too.

On 26/08/2019 00:23, Fredxx wrote:
On 25/08/2019 20:38, Harry Bloomfield wrote:
Tricky Dicky wrote :
RCD 1 80A

Kitchen - ring main with 2.5mm2 T&E with 32A MCB

Fridge and freezer on a none RCD circuit, to avoid food spoiling if
there is an RCD tripped in your absence?

Tricky unless you use SWA or pay a lot of detail to the cable route.


It's a CU swap not a rewire.

Strictly speaking all sockets should now be RCD protected inducing the
ones in the OP's loft.

--
Adam

On 25/08/2019 23:24, Robin wrote:
On 25/08/2019 23:08, Robin wrote:
On 25/08/2019 21:50, wrote:
On Sunday, 25 August 2019 19:59:32 UTC+1, ARWÂ* wrote:
A load of ******** here for you to read and forget
https://professional-electrician.com...d-as-standard/

"a relatively low-priced and widely available safety item"

low priced??

And isn't there a bit of a fire risk having something that goes
pftttt in a consumer unit? In the top photo it's wired across the
main switch and not even fused down



like many (most?) such it comes built in fuses so needs no additional
overcurrent protection.


ahem...except on (still not sober) reflection & checking that seems to
be one that does require external overcurrent protection


Type 1 and 2 SPDs are fitted at the origin and need no further
overcurrent protection.

Although BG do seem to have a typo right at the bottom (in the safety
warning)

https://www.bgelectrical.uk/public/d...on_Devices.pdf

--
Adam

It's a CU swap not a rewire.

Strictly speaking all sockets should now be RCD protected inducing the
ones in the OP's loft.

OK that is one "gotcha", I did not realise all sockets were to be RCD protected I thought it only applied those with wiring less than 50mm deep in the walls.

Just to clarify the alarm situation. When we first moved in the so called professionally installed alarm was useless. As a temporary measure because we knew the kitchen and bathroom were going to be re-done resulting in quite a lot of disruption and rewiring of the kitchen. I was loathe to start any work that involved major disruption until I had to. The system we bought was a wireless DIY system this meant that the control box and bell boxes each had their own wall wart PSUs. As a temporary measure and to keep the PSUs out of sight and out of mind sockets were located in a convenient place in the loft. These sockets were for convenience sake only for the alarm and wired into the light circuit which was not RCD protected a little naughty but the alarm at best draws minimum current about 200mA if I recall. The CU does not have any spare ways so there was not really much else that could be done at the time.

As well as the CU swap I am doing a partial rewire mainly the kitchen and separating the lighting circuit into two as described above and connecting the garage. The kitchen ring main will be completely new as at present all the sockets are in the wrong places with most of the if not replaced would end up above the middle of the hob along with several fixed appliance switches. Other rewiring involves putting the alarm sockets on a separate circuit instead of the lighting circuit and also the boiler which is in the airing cupboard and utilises the old immersion circuit, a fused spur unit in the cupboard with the feed going via a switch in the kitchen situated above the new hob position, the plan with the latter is to eliminate the remote switch and feed directly from the CU. Whilst pulling through the cable for the boiler I can draw two cables through to the airing including the proposed alarm cable which will be surface mounted in the airing cupboard.

So not quite a full rewire but well on the way. As implied before the CU was replaced sometime before we bought the house utilising all the old circuits apart from wiring in the shower. This left a messy arrangement of junction boxes dangling off cables as a result of repositioning the CU higher. The rewire will eliminate the junction boxes as the new CU will be lower now that some of the clutter in the way is being removed.

Richard

On 26/08/2019 09:27, ARW wrote:
On 25/08/2019 23:24, Robin wrote:
On 25/08/2019 23:08, Robin wrote:
On 25/08/2019 21:50, wrote:
On Sunday, 25 August 2019 19:59:32 UTC+1, ARWÂ* wrote:
A load of ******** here for you to read and forget
https://professional-electrician.com...d-as-standard/

"a relatively low-priced and widely available safety item"

low priced??

And isn't there a bit of a fire risk having something that goes
pftttt in a consumer unit? In the top photo it's wired across the
main switch and not even fused down



like many (most?) such it comes built in fuses so needs no additional
overcurrent protection.


ahem...except on (still not sober) reflection & checking that seems to
be one that does require external overcurrent protection


Type 1 and 2 SPDs are fitted at the origin and need no further
overcurrent protection.

That's me back in my rest state - i.e. confused

I'd got it in my head that SPDs needed overcurrent protection that
discriminates from the main fuse. From my doodles on a possible new CU
I seem to have got that from the page 49 of the BEAMA guide - but I see
that is only "should", not "must".

http://www.beama.org.uk/asset/1FE338...7F3DEA6C683C6/




--
Robin
reply-to address is (intended to be) valid

On 26/08/2019 10:13, Tricky Dicky wrote:
It's a CU swap not a rewire.

Strictly speaking all sockets should now be RCD protected inducing the
ones in the OP's loft.

OK that is one "gotcha", I did not realise all sockets were to be RCD protected I thought it only applied those with wiring less than 50mm deep in the walls.


Afraid so, even sockets fed from SWA or in trunking. However you could
feed a RCD socket with SWA or truncked cable.
The same now applies for lights in domestic properties.


--
Adam

On 25/08/2019 19:20, Tricky Dicky wrote:
It is getting to the point where I am ready to install my main CU so just checking for any "gotchas" that I have not considered.

The unit I am going for is this

https://www.toolstation.com/mk-metal...er-unit/p77771

Have you bought it yet?

Just I have spotted an alternative.


--
Adam

Tricky Dicky wrote:

ARW wrote:

Strictly speaking all sockets should now be RCD protected inducing the
ones in the OP's loft.

OK that is one "gotcha"

If you don't want that circuit to share an RCD with others, put it on an
RCBO instead of MCB?

On 26/08/2019 10:25, Robin wrote:
On 26/08/2019 09:27, ARW wrote:
On 25/08/2019 23:24, Robin wrote:
On 25/08/2019 23:08, Robin wrote:
On 25/08/2019 21:50, wrote:
On Sunday, 25 August 2019 19:59:32 UTC+1, ARWÂ* wrote:
A load of ******** here for you to read and forget
https://professional-electrician.com...d-as-standard/

"a relatively low-priced and widely available safety item"

low priced??

And isn't there a bit of a fire risk having something that goes
pftttt in a consumer unit? In the top photo it's wired across the
main switch and not even fused down



like many (most?) such it comes built in fuses so needs no
additional overcurrent protection.


ahem...except on (still not sober) reflection & checking that seems
to be one that does require external overcurrent protection


Type 1 and 2 SPDs are fitted at the origin and need no further
overcurrent protection.

That's me back in my rest state - i.e. confused

I'd got it in my head that SPDs needed overcurrent protection that
discriminates from the main fuse.Â* From my doodles on a possible new CU
I seem to have got that from the page 49 of the BEAMA guide - but I see
that is only "should", not "must".

http://www.beama.org.uk/asset/1FE338...7F3DEA6C683C6/





It seems some of them do require MCB protection.

--
Adam

On 25/08/2019 23:08, Robin wrote:
On 25/08/2019 21:50, wrote:
On Sunday, 25 August 2019 19:59:32 UTC+1, ARWÂ* wrote:
A load of ******** here for you to read and forget
https://professional-electrician.com...d-as-standard/

"a relatively low-priced and widely available safety item"

low priced??

And isn't there a bit of a fire risk having something that goes pftttt
in a consumer unit? In the top photo it's wired across the main switch
and not even fused down



like many (most?) such it comes built in fuses so needs no additional
overcurrent protection.



You would think it should handle thousands of amps or its not going to
do anything useful.

On 26/08/2019 11:31, dennis@home wrote:
On 25/08/2019 23:08, Robin wrote:
On 25/08/2019 21:50, wrote:
On Sunday, 25 August 2019 19:59:32 UTC+1, ARWÂ* wrote:
A load of ******** here for you to read and forget
https://professional-electrician.com...d-as-standard/

"a relatively low-priced and widely available safety item"

low priced??

And isn't there a bit of a fire risk having something that goes
pftttt in a consumer unit? In the top photo it's wired across the
main switch and not even fused down



like many (most?) such it comes built in fuses so needs no additional
overcurrent protection.



You would think it should handle thousands of amps or its not going to
do anything useful.


They can handle 10s of kA - but only for /very/ short periods.

The overcurrent protection is to protect the cables and SPD against faults.


--
Robin
reply-to address is (intended to be) valid

On 26/08/2019 11:56, Robin wrote:
On 26/08/2019 11:31, dennis@home wrote:
On 25/08/2019 23:08, Robin wrote:
On 25/08/2019 21:50, wrote:
On Sunday, 25 August 2019 19:59:32 UTC+1, ARWÂ* wrote:
A load of ******** here for you to read and forget
https://professional-electrician.com...d-as-standard/

"a relatively low-priced and widely available safety item"

low priced??

And isn't there a bit of a fire risk having something that goes
pftttt in a consumer unit? In the top photo it's wired across the
main switch and not even fused down



like many (most?) such it comes built in fuses so needs no additional
overcurrent protection.



You would think it should handle thousands of amps or its not going to
do anything useful.


They can handle 10s of kA - but only for /very/ short periods.

The overcurrent protection is to protect the cables and SPD against faults.



The company fuse should protect those.
Typically its 100A, mine is only 80A though.
Obviously if the SPD you buy specifies less then you need something
extra to protect it.

On 26/08/2019 12:07, dennis@home wrote:
On 26/08/2019 11:56, Robin wrote:
On 26/08/2019 11:31, dennis@home wrote:
On 25/08/2019 23:08, Robin wrote:
On 25/08/2019 21:50, wrote:
On Sunday, 25 August 2019 19:59:32 UTC+1, ARWÂ* wrote:
A load of ******** here for you to read and forget
https://professional-electrician.com...d-as-standard/

"a relatively low-priced and widely available safety item"

low priced??

And isn't there a bit of a fire risk having something that goes
pftttt in a consumer unit? In the top photo it's wired across the
main switch and not even fused down



like many (most?) such it comes built in fuses so needs no
additional overcurrent protection.



You would think it should handle thousands of amps or its not going
to do anything useful.


They can handle 10s of kA - but only for /very/ short periods.

The overcurrent protection is to protect the cables and SPD against
faults.



The company fuse should protect those.
Typically its 100A, mine is only 80A though.
Obviously if the SPD you buy specifies less then you need something
extra to protect it.


1. You may be happy to risk a faulty SPD taking out the "company fuse".
Others wouldn't.

2. Some SPDs specify maximum overcurrent protection of less than 80A -
including the one in photo (63A).

--
Robin
reply-to address is (intended to be) valid

Have you bought it yet?

Just I have spotted an alternative.

I have just come back from Toolsatan before reading your post. I got a further £10 off the price by using their recently introduced loyalty/identity card.

Incidentally the spend £60 or more and get £10 off offer ends today.

Richard

On 26/08/2019 12:35, Tricky Dicky wrote:

Have you bought it yet?

Just I have spotted an alternative.

I have just come back from Toolsatan before reading your post. I got a further £10 off the price by using their recently introduced loyalty/identity card.

Incidentally the spend £60 or more and get £10 off offer ends today.


Probably not the one I was looking at. The same offer I was looking at
ends on the 4th September.

It's still the same £10 saved:-)


--
Adam

On 26/08/2019 12:19, Robin wrote:
On 26/08/2019 12:07, dennis@home wrote:
On 26/08/2019 11:56, Robin wrote:
On 26/08/2019 11:31, dennis@home wrote:
On 25/08/2019 23:08, Robin wrote:
On 25/08/2019 21:50, wrote:
On Sunday, 25 August 2019 19:59:32 UTC+1, ARWÂ* wrote:
A load of ******** here for you to read and forget
https://professional-electrician.com...d-as-standard/

"a relatively low-priced and widely available safety item"

low priced??

And isn't there a bit of a fire risk having something that goes
pftttt in a consumer unit? In the top photo it's wired across the
main switch and not even fused down



like many (most?) such it comes built in fuses so needs no
additional overcurrent protection.



You would think it should handle thousands of amps or its not going
to do anything useful.


They can handle 10s of kA - but only for /very/ short periods.

The overcurrent protection is to protect the cables and SPD against
faults.



The company fuse should protect those.
Typically its 100A, mine is only 80A though.
Obviously if the SPD you buy specifies less then you need something
extra to protect it.


1.Â*Â*Â* You may be happy to risk a faulty SPD taking out the "company
fuse". Others wouldn't.

2.Â*Â*Â* Some SPDs specify maximum overcurrent protection of less than 80A
- including the one in photo (63A).


Then they are the wrong ones to use in that CU, unless you don't mind
your supply being reduced to 63A and you fit another fuse/breaker.

On 26/08/2019 13:42, dennis@home wrote:
On 26/08/2019 12:19, Robin wrote:
On 26/08/2019 12:07, dennis@home wrote:
On 26/08/2019 11:56, Robin wrote:
On 26/08/2019 11:31, dennis@home wrote:
On 25/08/2019 23:08, Robin wrote:
On 25/08/2019 21:50, wrote:
On Sunday, 25 August 2019 19:59:32 UTC+1, ARWÂ* wrote:
A load of ******** here for you to read and forget
https://professional-electrician.com...d-as-standard/

"a relatively low-priced and widely available safety item"

low priced??

And isn't there a bit of a fire risk having something that goes
pftttt in a consumer unit? In the top photo it's wired across the
main switch and not even fused down



like many (most?) such it comes built in fuses so needs no
additional overcurrent protection.



You would think it should handle thousands of amps or its not going
to do anything useful.


They can handle 10s of kA - but only for /very/ short periods.

The overcurrent protection is to protect the cables and SPD against
faults.



The company fuse should protect those.
Typically its 100A, mine is only 80A though.
Obviously if the SPD you buy specifies less then you need something
extra to protect it.


1.Â*Â*Â* You may be happy to risk a faulty SPD taking out the "company
fuse". Others wouldn't.

2.Â*Â*Â* Some SPDs specify maximum overcurrent protection of less than
80A - including the one in photo (63A).


Then they are the wrong ones to use in that CU, unless you don't mind
your supply being reduced to 63A and you fit another fuse/breaker.


You have misunderstood how SPDs work. They are in /parallel/ with the
circuits they protect. So an SPD which needs a max 32A MCB can happily
sit in a CU and protect 100A loads. See the BEAMA guide - link in one
of my earlier posts.
--
Robin
reply-to address is (intended to be) valid

On 26/08/2019 14:03, Robin wrote:
On 26/08/2019 13:42, dennis@home wrote:
On 26/08/2019 12:19, Robin wrote:
On 26/08/2019 12:07, dennis@home wrote:
On 26/08/2019 11:56, Robin wrote:
On 26/08/2019 11:31, dennis@home wrote:
On 25/08/2019 23:08, Robin wrote:
On 25/08/2019 21:50, wrote:
On Sunday, 25 August 2019 19:59:32 UTC+1, ARWÂ* wrote:
A load of ******** here for you to read and forget
https://professional-electrician.com...d-as-standard/

"a relatively low-priced and widely available safety item"

low priced??

And isn't there a bit of a fire risk having something that goes
pftttt in a consumer unit? In the top photo it's wired across
the main switch and not even fused down



like many (most?) such it comes built in fuses so needs no
additional overcurrent protection.



You would think it should handle thousands of amps or its not
going to do anything useful.


They can handle 10s of kA - but only for /very/ short periods.

The overcurrent protection is to protect the cables and SPD against
faults.



The company fuse should protect those.
Typically its 100A, mine is only 80A though.
Obviously if the SPD you buy specifies less then you need something
extra to protect it.


1.Â*Â*Â* You may be happy to risk a faulty SPD taking out the "company
fuse". Others wouldn't.

2.Â*Â*Â* Some SPDs specify maximum overcurrent protection of less than
80A - including the one in photo (63A).


Then they are the wrong ones to use in that CU, unless you don't mind
your supply being reduced to 63A and you fit another fuse/breaker.


You have misunderstood how SPDs work.Â* They are in /parallel/ with the
circuits they protect. So an SPD which needs a max 32A MCB can happily
sit in a CU and protect 100A loads.Â* See the BEAMA guide - link in one
of my earlier posts.

It can but MCBs and RCDs have coils in them so don't expect the same
surge protection if the surge current has to traverse breakers.
To work well, they need a low impedance at a higher frequency than mains
so even small coils will have an effect.

Take the point about the fridge/freezer supply having plenty of spare ways at the moment so I will provide a radial for that socket but with cables buried in the wall I will protect that circuit with an RCBO, would 16A be alright?

I might as well do the same for my Alarm circuit, all the rest less critical circuits will be shared with the two RCDs.

Richard

On 26/08/2019 14:37, Tricky Dicky wrote:
Take the point about the fridge/freezer supply having plenty of spare ways at the moment so I will provide a radial for that socket but with cables buried in the wall I will protect that circuit with an RCBO, would 16A be alright?

I might as well do the same for my Alarm circuit, all the rest less critical circuits will be shared with the two RCDs.


Yes.



But get ready for tales of woe when the lights go out on a shared RCD
and you will need emergency lighting on your stairs (NT normally
provides "facts" about this for my amusement)

Or just congratulate yourself on buying a very good CU at a very good price.






--
Adam

On 26/08/2019 14:36, dennis@home wrote:
snip
The company fuse should protect those.
Typically its 100A, mine is only 80A though.
Obviously if the SPD you buy specifies less then you need something
extra to protect it.


1.Â*Â*Â* You may be happy to risk a faulty SPD taking out the "company
fuse". Others wouldn't.

2.Â*Â*Â* Some SPDs specify maximum overcurrent protection of less than
80A - including the one in photo (63A).


Then they are the wrong ones to use in that CU, unless you don't mind
your supply being reduced to 63A and you fit another fuse/breaker.


You have misunderstood how SPDs work.Â* They are in /parallel/ with the
circuits they protect. So an SPD which needs a max 32A MCB can happily
sit in a CU and protect 100A loads.Â* See the BEAMA guide - link in one
of my earlier posts.

It can but MCBs and RCDs have coils in them so don't expect the same
surge protection if the surge current has to traverse breakers.
To work well, they need a low impedance at a higher frequency than mains
so even small coils will have an effect.

If you are worried about that then use a fuse rather than an MCB, or use
an SPD with integral overcurrent protection so it's all taken into
account in the specs.


--
Robin
reply-to address is (intended to be) valid

On 26/08/2019 08:25, ARW wrote:
On 26/08/2019 00:23, Fredxx wrote:
On 25/08/2019 20:38, Harry Bloomfield wrote:
Tricky Dicky wrote :
RCD 1 80A

Kitchen - ring main with 2.5mm2 T&E with 32A MCB

Fridge and freezer on a none RCD circuit, to avoid food spoiling if
there is an RCD tripped in your absence?

Tricky unless you use SWA or pay a lot of detail to the cable route.


It's a CU swap not a rewire.

Strictly speaking all sockets should now be RCD protected inducing the
ones in the OP's loft.

I thought a CU swap counted as a rewire?

Would a fused outlet to the freezer also need RCD protection? DO the new
rules apply to all 'outlets'?

On 26/08/2019 16:18, Fredxx wrote:
On 26/08/2019 08:25, ARW wrote:
On 26/08/2019 00:23, Fredxx wrote:
On 25/08/2019 20:38, Harry Bloomfield wrote:
Tricky Dicky wrote :
RCD 1 80A

Kitchen - ring main with 2.5mm2 T&E with 32A MCB

Fridge and freezer on a none RCD circuit, to avoid food spoiling if
there is an RCD tripped in your absence?

Tricky unless you use SWA or pay a lot of detail to the cable route.


It's a CU swap not a rewire.

Strictly speaking all sockets should now be RCD protected inducing the
ones in the OP's loft.

I thought a CU swap counted as a rewire?


It's not. Trust me.

It is however one of the three notifiable Part P jobs.



Would a fused outlet to the freezer also need RCD protection? DO the new
rules apply to all 'outlets'?



I sometimes look forward to meeting the apprentices.



--
Adam

On 26/08/2019 08:25, ARW wrote:
On 26/08/2019 00:23, Fredxx wrote:
On 25/08/2019 20:38, Harry Bloomfield wrote:
Tricky Dicky wrote :
RCD 1 80A

Kitchen - ring main with 2.5mm2 T&E with 32A MCB

Fridge and freezer on a none RCD circuit, to avoid food spoiling if
there is an RCD tripped in your absence?

Tricky unless you use SWA or pay a lot of detail to the cable route.


It's a CU swap not a rewire.

Strictly speaking all sockets should now be RCD protected inducing the
ones in the OP's loft.


So you are up in the loft faffing about using something electrical
when suddenly POP, off goes all the lights, and you then end up in the
bedroom via the most direct route ?.`

On 26/08/2019 10:53, ARW wrote:
On 25/08/2019 19:20, Tricky Dicky wrote:
It is getting to the point where I am ready to install my main CU so
just checking for any "gotchas" that I have not considered.

The unit I am going for is this

https://www.toolstation.com/mk-metal...er-unit/p77771


Have you bought it yet?

Just I have spotted an alternative.



Don't keep us in suspense !

On 26/08/2019 20:37, Andrew wrote:
On 26/08/2019 10:53, ARW wrote:
On 25/08/2019 19:20, Tricky Dicky wrote:
It is getting to the point where I am ready to install my main CU so
just checking for any "gotchas" that I have not considered.

The unit I am going for is this

https://www.toolstation.com/mk-metal...er-unit/p77771


Have you bought it yet?

Just I have spotted an alternative.



Don't keep us in suspense !

I had spotted this

https://www.screwfix.com/p/british-g...mer-unit/1460x

It would need a few extra RCBOs but they are only £15 at TLC.

--
Adam

On 26/08/2019 20:34, Andrew wrote:
On 26/08/2019 08:25, ARW wrote:
On 26/08/2019 00:23, Fredxx wrote:
On 25/08/2019 20:38, Harry Bloomfield wrote:
Tricky Dicky wrote :
RCD 1 80A

Kitchen - ring main with 2.5mm2 T&E with 32A MCB

Fridge and freezer on a none RCD circuit, to avoid food spoiling if
there is an RCD tripped in your absence?

Tricky unless you use SWA or pay a lot of detail to the cable route.


It's a CU swap not a rewire.

Strictly speaking all sockets should now be RCD protected inducing the
ones in the OP's loft.


So you are up in the loft faffing about using something electrical
when suddenly POP, off goes all the lights, and you then end up in the
bedroom via the most direct route ?.`



Well that depends if you fell trough the loft just because it went dark
or if it whet dark whist getting an electric shock!

--
Adam