New Consumer Unit

[Jeff Gaines]

Now my new boiler is up and running I want to have my consumer unit
replaced. Much as I would like to DIY it is beyond my physical abilities
and in any event needs to be certified. I have a quote as follows:

***********
To supply and install a new 18th edition consumer unit, replacing the
existing dated fuse board. The new board will be metal clad and
incorporate RCBO's in order to apply the required RCD protection. The main
supply tails and earthing conductor will also be upgraded. A surge
protective device (SPD) will also be installed. Clear and formal circuit
identification will be applied. All supply cables entering DB-1 will be
adequately supported and containment will be installed The new DB will be
installed and fully comply with wiring regulation BS7671.

This cost is based on the existing bonding being suitably sized.

We have also allowed to test the system upon completion but please be
aware that should there be any issues identified that prevent
certification to be completed, these would need to be rectified
additionally prior to certification being issued.

£695 + VAT = £834
***********

The electrician is the one the plumber used to wire up the new controller
and he made a very neat job of that.

Does that seem to fit the bill?

Should I specify a make (or choice of makes) for the consumer unit to
ensure it is a decent one?

Anything else I should check?

Current unit is a MEM Memera 2000 with 7 connections - mix of fuses and RCD.

[alan_m]

Post by Jeff Gaines
Anything else I should check?
Current unit is a MEM Memera 2000 with 7 connections - mix of fuses and RCD.

Possibly make provision for future additions such as a EV charging point
and have extra spaces, and capacity, for future equipment you may need
in old age to support continued living in your own home.

Isolation switch between the DNO (Distribution Network Operator)incoming
fuse and the consumer unit.

[Andy Burns]

Post by Jeff Gaines
To supply and install a new 18th edition consumer unit, replacing the
existing dated fuse board. The new board will be metal clad and
incorporate RCBO's in order to apply the required RCD protection. The
main supply tails and earthing conductor will also be upgraded. A surge
protective device (SPD) will also be installed. Clear and formal circuit
identification will be applied. All supply cables entering DB-1 will be
adequately supported and containment will be installed The new DB will
be installed and fully comply with wiring regulation BS7671.

All sounds reasonable for what you'd expect to be fitted now.

But would have thought they'd do an EICR beforehand so that they know
the state of ring continuity, insulation resistance, supply earth
impedance, missing earth on old lighting circuits, borrowed neutrals,
etc otherwise they could end up finding issues after the new board is
fitted ...

Post by Jeff Gaines
This cost is based on the existing bonding being suitably sized.
We have also allowed to test the system upon completion but please be
aware that should there be any issues identified that prevent
certification to be completed, these would need to be rectified
additionally prior to  certification being issued.
£695 + VAT = £834
***********
The electrician is the one the plumber used to wire up the new
controller and he made a very neat job of that.
Does that seem to fit the bill?
Should I specify a make (or choice of makes) for the consumer unit to
ensure it is a decent one?

As they've quoted a price, I expect that's based on their favoured brand.

[ARW]

Post by Andy Burns
But would have thought they'd do an EICR beforehand so that they know
the state of ring continuity, insulation resistance, supply earth
impedance, missing earth on old lighting circuits, borrowed neutrals,
etc otherwise they could end up finding issues after the new board is
fitted ...

That's the point of testing afterwards......

If nothing trips and there are no problems you have just charged £695
for £160 of parts (that you can claim the VAT back on) for three hours
of labour to swap the CU and do a basic test.

Do a proper EICR for 4-5 hours before the CU swap and you should know
all the faults beforehand and be able to tell the customer the real cost
of the remedial works.

[John Rumm]

Post by Jeff Gaines
Now my new boiler is up and running I want to have my consumer unit
replaced. Much as I would like to DIY it is beyond my physical abilities
***********
To supply and install a new 18th edition consumer unit, replacing the
existing dated fuse board. The new board will be metal clad and
incorporate RCBO's in order to apply the required RCD protection. The
main supply tails and earthing conductor will also be upgraded. A surge
protective device (SPD) will also be installed. Clear and formal circuit
identification will be applied. All supply cables entering DB-1 will be
adequately supported and containment will be installed The new DB will
be installed and fully comply with wiring regulation BS7671.
This cost is based on the existing bonding being suitably sized.
We have also allowed to test the system upon completion but please be
aware that should there be any issues identified that prevent
certification to be completed, these would need to be rectified
additionally prior to  certification being issued.
£695 + VAT = £834
***********
The electrician is the one the plumber used to wire up the new
controller and he made a very neat job of that.
Does that seem to fit the bill?

Well if using decent quality parts and assuming he means all circuits
are RCBO protected, then £250 of that is materials... (based on a quick
pricing assuming 8 circuits in a 10 way Hager CU)

So all RCBO is good - better discrimination under fault conditions, and
less risk of nuisance RCD trips.

I expect he has factored in some time to allow for fixing existent
faults that may not be apparent at the moment (like borrowed neutrals etc).

Post by Jeff Gaines
Should I specify a make (or choice of makes) for the consumer unit to
ensure it is a decent one?

Might be worth enquiring what he would use...

Post by Jeff Gaines
Anything else I should check?
Current unit is a MEM Memera 2000 with 7 connections - mix of fuses and RCD.

Aside from not being shiny and new, what is wrong with the current setup?
--
Cheers,

John.

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\=================================================================/

[Jeff Gaines]

Post by John Rumm

Post by Jeff Gaines
Current unit is a MEM Memera 2000 with 7 connections - mix of fuses and RCD.

Aside from not being shiny and new, what is wrong with the current setup?

Good question! If a fuse goes in the current unit it is a PITA to replace
involving poking the fuse upwards then lifting it out. The pendant in the
study blows the fuse when a bulb goes, don't know if that was a weak fuse
or defective pendant (they will check it as n extra job).

I think the idea of an update and check is what drove me to it!

[Andrew]

Post by Jeff Gaines

Post by John Rumm

Post by Jeff Gaines
Current unit is a MEM Memera 2000 with 7 connections - mix of fuses and RCD.

Aside from not being shiny and new, what is wrong with the current setup?

Good question! If a fuse goes in the current unit it is a PITA to replace

The only time any of my Wylex rewireble fuses ever 'went' was after
someone (cough) shorted something out. Ouch.

[Fredxx]

Post by Andrew

Post by Jeff Gaines

Post by John Rumm

Post by Jeff Gaines
Current unit is a MEM Memera 2000 with 7 connections - mix of fuses and RCD.

Aside from not being shiny and new, what is wrong with the current setup?

Good question! If a fuse goes in the current unit it is a PITA to replace

The only time any of my Wylex rewireble fuses ever 'went' was after
someone (cough) shorted something out. Ouch.

I have known incandescents take out fuses and MCBs, but not known such
with more recent lamp developments.

[Andrew]

Post by Fredxx

Post by Andrew

Post by Jeff Gaines

Post by John Rumm

Post by Jeff Gaines
Current unit is a MEM Memera 2000 with 7 connections - mix of fuses and RCD.

Aside from not being shiny and new, what is wrong with the current setup?

Good question! If a fuse goes in the current unit it is a PITA to replace

The only time any of my Wylex rewireble fuses ever 'went' was after
someone (cough) shorted something out. Ouch.

I have known incandescents take out fuses and MCBs, but not known such
with more recent lamp developments.

Yup, cheapo supermarket bulbs. Good quality Osram, or similar
never did this (AFAIK)

[nib]

Post by Andrew

Post by Fredxx

Post by Andrew

Post by Jeff Gaines

Post by John Rumm

Post by Jeff Gaines
Current unit is a MEM Memera 2000 with 7 connections - mix of fuses and RCD.

Aside from not being shiny and new, what is wrong with the current setup?

Good question! If a fuse goes in the current unit it is a PITA to replace

The only time any of my Wylex rewireble fuses ever 'went' was after
someone (cough) shorted something out. Ouch.

I have known incandescents take out fuses and MCBs, but not known such
with more recent lamp developments.

Yup, cheapo supermarket bulbs. Good quality Osram, or similar
never did this (AFAIK)

A decade or two ago, I found the bulbs that nearly always tripped the
breaker when they failed were Philips "Hint of ..." tinted bulbs!

nib

[John Rumm]

Post by Andrew

Post by Fredxx

Post by Andrew

Post by Jeff Gaines

Post by John Rumm

Post by Jeff Gaines
Current unit is a MEM Memera 2000 with 7 connections - mix of fuses and RCD.

Aside from not being shiny and new, what is wrong with the current setup?

Good question! If a fuse goes in the current unit it is a PITA to replace

The only time any of my Wylex rewireble fuses ever 'went' was after
someone (cough) shorted something out. Ouch.

I have known incandescents take out fuses and MCBs, but not known such
with more recent lamp developments.

Yup, cheapo supermarket bulbs. Good quality Osram, or similar
never did this (AFAIK)

GU10 mains halogens were quite prone to it...

(I used to fit type C MCBs for the lighting circuits - that usually
stopped it)
--
Cheers,

John.

/=================================================================\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\=================================================================/

[Andrew]

Post by John Rumm

Post by Jeff Gaines
Now my new boiler is up and running I want to have my consumer unit
replaced. Much as I would like to DIY it is beyond my physical
abilities and in any event needs to be certified. I have a quote as
***********
To supply and install a new 18th edition consumer unit, replacing the
existing dated fuse board. The new board will be metal clad and
incorporate RCBO's in order to apply the required RCD protection. The
main supply tails and earthing conductor will also be upgraded. A
surge protective device (SPD) will also be installed. Clear and formal
circuit identification will be applied. All supply cables entering
DB-1 will be adequately supported and containment will be installed
The new DB will be installed and fully comply with wiring regulation
BS7671.
This cost is based on the existing bonding being suitably sized.
We have also allowed to test the system upon completion but please be
aware that should there be any issues identified that prevent
certification to be completed, these would need to be rectified
additionally prior to  certification being issued.
£695 + VAT = £834
***********
The electrician is the one the plumber used to wire up the new
controller and he made a very neat job of that.
Does that seem to fit the bill?

Well if using decent quality parts and assuming he means all circuits
are RCBO protected, then £250 of that is materials... (based on a quick
pricing assuming 8 circuits in a 10 way Hager CU)
So all RCBO is good - better discrimination under fault conditions, and
less risk of nuisance RCD trips.
I expect he has factored in some time to allow for fixing existent
faults that may not be apparent at the moment (like borrowed neutrals etc).

Post by Jeff Gaines
Should I specify a make (or choice of makes) for the consumer unit to
ensure it is a decent one?

Might be worth enquiring what he would use...

Post by Jeff Gaines
Anything else I should check?
Current unit is a MEM Memera 2000 with 7 connections - mix of fuses and RCD.

Aside from not being shiny and new, what is wrong with the current setup?

+1 !!!


He already has RCD protection, though it sounds as if there is only
a single RCD. This is a 1983 property. What Wiring regs were in force
then ?

Because he seems to have a lot of computer stuff over and above an
average person, a single RCD installation might be tempting fate.

[Jeff Gaines]

Post by Andrew

Post by John Rumm
Aside from not being shiny and new, what is wrong with the current setup?

+1 !!!
He already has RCD protection, though it sounds as if there is only
a single RCD. This is a 1983 property. What Wiring regs were in force
then ?
Because he seems to have a lot of computer stuff over and above an
average person, a single RCD installation might be tempting fate.

It is one RCD (or whatever they are called now) per circuit, it's just
part of keeping things up to date.

[John Rumm]

Post by Jeff Gaines

Post by Andrew

Post by John Rumm
Aside from not being shiny and new, what is wrong with the current setup?

+1 !!!
He already has RCD protection, though it sounds as if there is only
a single RCD. This is a 1983 property. What Wiring regs were in force
then ?

15th Edition - so "whole house" RCDs were a thing.

https://wiki.diyfaq.org.uk/index.php/Wiring_regs_history

Post by Jeff Gaines

Post by Andrew
Because he seems to have a lot of computer stuff over and above an
average person, a single RCD installation might be tempting fate.

It is one RCD (or whatever they are called now) per circuit, it's just
part of keeping things up to date.

MCB - Miniature Circuit Breaker - trips on overcurrent - either very
short term "fault" currents, or longer terms sustained "overload" currents.

RCD - Residual Current Device - trips on a imbalance between current
flowing in live and neutral (normally indicating some is returning to
earth via some unexpected path - possibly you!)

RCBO - Residual Current (circuit) Breaker with Overload protection -
basically a combination of the above two.

So MCB and Fuses protect the installation, and also give shock
protection when combined with earthing and equipotential bonding.

RCDs give greatly enhanced shock protection by sensing dangerous
conditions that would not cause a fuse / MCB to trip.

So RCDs are generally a good thing, however if one device protects too
many circuits the chances of a nuisance trip increases since their
"budget" for leakage current is shared across the installation. Also you
lose all discrimination - any fault knocks out all of the circuits -
rather than the ideal where a fault only trips the circuit with the fault.

So good reasons why you might want to change:

Current install is damaged or directly unsafe.

To replace "whole house" RCD protection (or add RCD protection for the
first time)

You need more "ways" to accommodate more circuits.

You have rewireable fuses and fear they may be abused, or that they
might be difficult to fix should they blow.

You have a plastic or wood CU and are concerned it might be a fire risk.

You are getting nuisance trips on RCDs and would like more RCDs or RCDs
on all circuits (i.e. all RCBO) to mitigate the chance of trips.
--
Cheers,

John.

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| John Rumm - john(at)internode(dot)co(dot)uk |
\=================================================================/

[Roger Mills]

Post by Jeff Gaines

Post by Andrew

Post by John Rumm
Aside from not being shiny and new, what is wrong with the current setup?

+1 !!!
He already has RCD protection, though it sounds as if there is only
a single RCD. This is a 1983 property. What Wiring regs were in force
then ?
Because he seems to have a lot of computer stuff over and above an
average person, a single RCD installation might be tempting fate.

It is one RCD (or whatever they are called now) per circuit, it's just
part of keeping things up to date.

Any chance of a photo of the current setup?

[Peter Johnson]

Post by Jeff Gaines
Now my new boiler is up and running I want to have my consumer unit
replaced. Much as I would like to DIY it is beyond my physical abilities
***********
To supply and install a new 18th edition consumer unit, replacing the
existing dated fuse board. The new board will be metal clad and
incorporate RCBO's in order to apply the required RCD protection. The main
supply tails and earthing conductor will also be upgraded. A surge
protective device (SPD) will also be installed. Clear and formal circuit
identification will be applied. All supply cables entering DB-1 will be
adequately supported and containment will be installed The new DB will be
installed and fully comply with wiring regulation BS7671.
This cost is based on the existing bonding being suitably sized.
We have also allowed to test the system upon completion but please be
aware that should there be any issues identified that prevent
certification to be completed, these would need to be rectified
additionally prior to certification being issued.
£695 + VAT = £834
***********

A passing electrician who thought I might be good for providing some
extra business gave me a spontaneous/off the cuff quote of 'about
£1,200' for replacing my 10-year-old CU last year. No discussion about
what it would include/exclude and I haven't seen any need to replace
the existing. He had a nice liveried van, though, for a two-man
business.

[Jeff Gaines]

Post by Jeff Gaines
Should I specify a make (or choice of makes) for the consumer unit to
ensure it is a decent one?

They have said they would fit a "Fusebox consumer unit", does that sound OK?

[Theo]

Post by Jeff Gaines

Post by Jeff Gaines
Should I specify a make (or choice of makes) for the consumer unit to
ensure it is a decent one?

They have said they would fit a "Fusebox consumer unit", does that sound OK?

It's a budget brand, been going since 2017:
https://consumerunitworld.co.uk/fusebox-389-c.asp

Sounds ok, in that the budget brands are still held to the same standards
as everyone else so they should work as expected. The one question with
budget brands is whether they're going to be around in years to come when
you need to add extra circuits or otherwise modify the installation.

In theory you are only supposed to use components that the manufacturer has
specified will work together, which means sticking will all one brand. eg
there can be issues fitting busbars from one brand into the terminals of
another. Not something that can't be worked around (worst case you could
just use a wire), but less than ideal.

My CU replacement in 2021 was a similar scale job and similar price to
yours, but that included using Hager components. They had suggested Fusebox
but I asked them to upgrade as I may put in further circuits in future.
OTOH there's been inflation since then, which maybe covers the difference.

Theo

[The Natural Philosopher]

Post by Theo

Post by Jeff Gaines

Post by Jeff Gaines
Should I specify a make (or choice of makes) for the consumer unit to
ensure it is a decent one?

They have said they would fit a "Fusebox consumer unit", does that sound OK?

https://consumerunitworld.co.uk/fusebox-389-c.asp
Sounds ok, in that the budget brands are still held to the same standards
as everyone else so they should work as expected. The one question with
budget brands is whether they're going to be around in years to come when
you need to add extra circuits or otherwise modify the installation.
In theory you are only supposed to use components that the manufacturer has
specified will work together, which means sticking will all one brand. eg
there can be issues fitting busbars from one brand into the terminals of
another. Not something that can't be worked around (worst case you could
just use a wire), but less than ideal.
My CU replacement in 2021 was a similar scale job and similar price to
yours, but that included using Hager components. They had suggested Fusebox
but I asked them to upgrade as I may put in further circuits in future.
OTOH there's been inflation since then, which maybe covers the difference.
Theo

I think this is sound advice.
If I were to redo my CU today I would fit RCBOs to all 13A outlets and a
main RCD of around 100mA to the whole box and use a brand that I knew
would be around for as long as MK has. And leave some extra places for
expansion.

Even if it cost another couple of hundred.

[Andy Burns]

Post by The Natural Philosopher
If I were to redo my CU today I would fit RCBOs to all 13A outlets and a
main RCD of around 100mA to the whole box

Are you a TT supply? I though not with your mention of replacement
transformers etc ... why add a single point of potential nuisance trips?

Post by The Natural Philosopher
and use a brand that I knew would be around for as long as MK has.

Are MK that safe nowadays? They announced in 2019 they were stopping
doing CUs, then changed their mind.

Look in the footer of <https://mksentrycircuitprotection.co.uk>

The MK brand is owned by Novar ED&S, in turn by Novar Holdings, who are
in liquidation, the head office is Honeywell House, which reflects the
previous owner, the UK factory at St Asaph is gone, now made in China by
Yihua ...

[The Natural Philosopher]

Post by The Natural Philosopher
If I were to redo my CU today I would fit RCBOs to all 13A outlets and
a main RCD of around 100mA to the whole box

Are you a TT supply?  I though not with your mention of replacement
transformers etc ... why add a single point of potential nuisance trips?

I can never remember what I am, I both have an earth supplied from the
transformer substation AND a copper stake in the ground :-)

The reason for an overall RCD is that it is a handy way to trip circuits
that are unlikely to be accessed by humans and so have no RCBO. E.g mice
chewing through cooker cables and lighting cables.

With a lot of electronic equipment 30mA is very much on the edge for a
large installation

Post by The Natural Philosopher
and use a brand that I knew would be around for as long as MK has.

Are MK that safe nowadays?  They announced in 2019 they were stopping
doing CUs, then changed their mind.

I didnt say MK but a brand that has been around for a while.

Look in the footer of <https://mksentrycircuitprotection.co.uk>
The MK brand is owned by Novar ED&S, in turn by Novar Holdings, who are
in liquidation, the head office is Honeywell House, which reflects the
previous owner, the UK factory at St Asaph is gone, now made in China by
Yihua ...

Sad. Well we all know other 'well known' brands. Simply look into
Screwfix and see what is selling

[Theo]

Post by The Natural Philosopher

Post by Theo

Post by Jeff Gaines

Post by Jeff Gaines
Should I specify a make (or choice of makes) for the consumer unit to
ensure it is a decent one?

They have said they would fit a "Fusebox consumer unit", does that sound OK?

https://consumerunitworld.co.uk/fusebox-389-c.asp
Sounds ok, in that the budget brands are still held to the same standards
as everyone else so they should work as expected. The one question with
budget brands is whether they're going to be around in years to come when
you need to add extra circuits or otherwise modify the installation.
In theory you are only supposed to use components that the manufacturer has
specified will work together, which means sticking will all one brand. eg
there can be issues fitting busbars from one brand into the terminals of
another. Not something that can't be worked around (worst case you could
just use a wire), but less than ideal.
My CU replacement in 2021 was a similar scale job and similar price to
yours, but that included using Hager components. They had suggested Fusebox
but I asked them to upgrade as I may put in further circuits in future.
OTOH there's been inflation since then, which maybe covers the difference.
Theo

I think this is sound advice.
If I were to redo my CU today I would fit RCBOs to all 13A outlets and a
main RCD of around 100mA to the whole box and use a brand that I knew
would be around for as long as MK has. And leave some extra places for
expansion.
Even if it cost another couple of hundred.

Given the costs of labour, spending a little more on materials seems to make
sense to me. Getting a bigger board with some extra blank slots costs a
couple of quid more but may come in handy in case you (or whoever you might
sell to) want to install heat pump, solar panels, EV charger, battery, ...
in decades to come. Unless you're super tight on space it's just a few more
inches in width and some extra metal, but buys you breathing space down the
road.

Although MK doesn't have a good reputation these days - they were bought out
by Honeywell and made cheaper/nastier (see the MK Essentials debacle).
They still sell garage-style CUs but aren't a big player in the whole-house
CU market any more. But I think they do still sell MCBs/RCBOs that are
compatible with their old boards, so you do get that longevity.

Theo

[Fredxx]

On 20/02/2025 11:19, The Natural Philosopher wrote:

<snip>

Post by The Natural Philosopher
If I were to redo my CU today I would fit RCBOs to all 13A outlets and a
main RCD of around 100mA to the whole box and use a brand that I knew
would be around for as long as MK has. And leave some extra places for
expansion.

Except there really is no need for the main 100mA RCD and it would serve
no purpose apart from creating nuisance tripping.

If the supply had very long tails then perhaps I can perhaps understand
the 100mA RCD closer to the supply but it should then be one with a time
delay for discrimination.

[ARW]

Post by Fredxx
<snip>

Post by The Natural Philosopher
If I were to redo my CU today I would fit RCBOs to all 13A outlets and
a main RCD of around 100mA to the whole box and use a brand that I
knew would be around for as long as MK has. And leave some extra
places for expansion.

Except there really is no need for the main 100mA RCD and it would serve
no purpose apart from creating nuisance tripping.
If the supply had very long tails then perhaps I can perhaps understand
the 100mA RCD closer to the supply but it should then be one with a time
delay for discrimination.

It must always be a time delayed 100mA RCD if used with 30mA RCD further
down the line.

It does not matter where you put the 100mA RCD - close to the CU or
close to the CU - remember a RCD only checks for an imbalance of current.