I have a Wylex Consumer unit with rewireable fuses. The cooker fuse is
30A (Red) which I need to change to 15A (Blue). Do I have to change
the backplate as well as the fuse, as the cable is still rated at 30A
so the 30A fuse could safely be reinstated for a future appliance (6mm
cable). I just want to fuse the current cooker with a lower value as
it has a gas hob.
So the question is - is putting a 15A fuse in a 30A fuseway against
any regs?

Thanks

John

On Mon, 15 Dec 2008 06:49:57 -0800 (PST), JohnW
wrote:

I have a Wylex Consumer unit with rewireable fuses. The cooker fuse is
30A (Red) which I need to change to 15A (Blue). Do I have to change
the backplate as well as the fuse, as the cable is still rated at 30A
so the 30A fuse could safely be reinstated for a future appliance (6mm
cable). I just want to fuse the current cooker with a lower value as
it has a gas hob.
So the question is - is putting a 15A fuse in a 30A fuseway against
any regs?

It would be much neater and safer to fit a 15A backplate (or a 16A
MCB) to avoid any confusion at a later date.

--
Frank Erskine

On 15 Dec, 14:49, JohnW wrote:
I have a Wylex Consumer unit with rewireable fuses. The cooker fuse is
30A (Red) which I need to change to 15A (Blue). Do I have to change
the backplate as well as the fuse, as the cable is still rated at 30A
so the 30A fuse could safely be reinstated for a future appliance (6mm
cable). *I just want to fuse the current cooker with a lower value as
it has a gas hob.
So the question is - is putting a 15A fuse in a 30A fuseway against
any regs?

Thanks

John

Not against regs .. .if you want to use a lower A fuse holder then you
would need to change the plastic back plate.
So rewire with fusewire you want and save the money - you can always
attach a label to advise.

JohnW wrote:
I have a Wylex Consumer unit with rewireable fuses. The cooker fuse is
30A (Red) which I need to change to 15A (Blue). Do I have to change
the backplate as well as the fuse, as the cable is still rated at 30A
so the 30A fuse could safely be reinstated for a future appliance (6mm
cable). I just want to fuse the current cooker with a lower value as
it has a gas hob.
So the question is - is putting a 15A fuse in a 30A fuseway against
any regs?

The 15A fuse former[1] (blue dots) won't fit the 30A backplate - so to
actually change it would require you change the back bit as well (they
usually come as a set anyway - but it does mean playing near exposed
live parts since you will need to take the front off the CU to change it).

You could however just label it carefully and use a lower rating of fuse
wire.

[1] I am assuming you really mean rewireable holders rather than
cartridge fuse holders. If the latter then the fuses are different sizes
and won't fit the wrong carrier.


--
Cheers,

John.

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

On Mon, 15 Dec 2008 16:00:19 +0000, John Rumm
wrote:

JohnW wrote:
I have a Wylex Consumer unit with rewireable fuses. The cooker fuse is
30A (Red) which I need to change to 15A (Blue). Do I have to change
the backplate as well as the fuse, as the cable is still rated at 30A
so the 30A fuse could safely be reinstated for a future appliance (6mm
cable). I just want to fuse the current cooker with a lower value as
it has a gas hob.
So the question is - is putting a 15A fuse in a 30A fuseway against
any regs?

The 15A fuse former[1] (blue dots) won't fit the 30A backplate - so to
actually change it would require you change the back bit as well (they
usually come as a set anyway - but it does mean playing near exposed
live parts since you will need to take the front off the CU to change it).

You don't actually need to take the front off the CU - all you do is
(carefully) remove the single fixing screw for the backplate and lift
it out.
Refitting is the reverse of the above - but be careful as the busbar
behind is live and it's easy to catch the screw on it.

--
Frank Erskine

The 15A fuse former[1] (blue dots) won't fit the 30A backplate - so to
actually change it would require you change the back bit as well (they
usually come as a set anyway - but it does mean playing near *exposed
live parts since you will need to take the front off the CU to change it)..

You could however just label it carefully and use a lower rating of fuse
wire.

Thanks - that is what I will do. It will also make me get a card of
fuse wire for my daughter's house as I threw mine away 20 years ago
when I moved and got a cartridge fuse consumer unit. You never know
when you will need it.

Interestingly, the cooker has two ovens with ratings of 2.4/2.7 Kw
and 1.8/2.0 Kw at 230/240 V and specifies 4mm cable for connection. It
then specifies it should be fused at 13A, which seems a bit light to
me!

John

Frank Erskine wrote:

You don't actually need to take the front off the CU - all you do is
(carefully) remove the single fixing screw for the backplate and lift
it out.
Refitting is the reverse of the above - but be careful as the busbar
behind is live and it's easy to catch the screw on it.

So play safe and switch off the main switch while working on it.

--
Mike Clarke

Frank Erskine wrote:

The 15A fuse former[1] (blue dots) won't fit the 30A backplate - so to
actually change it would require you change the back bit as well (they
usually come as a set anyway - but it does mean playing near exposed
live parts since you will need to take the front off the CU to change it).

You don't actually need to take the front off the CU - all you do is
(carefully) remove the single fixing screw for the backplate and lift
it out.

Yup, I think you are right if you don't need access to the circuit wires...

Refitting is the reverse of the above - but be careful as the busbar
behind is live and it's easy to catch the screw on it.

If in doubt, turn off the main switch - then the only live bit is still
under cover (unless you are right up against the switch end, where if
memory serves, you may be able to poke something into the metalwork near
the top of the switch).


--
Cheers,

John.

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

JohnW wrote:
The 15A fuse former[1] (blue dots) won't fit the 30A backplate - so to
actually change it would require you change the back bit as well (they
usually come as a set anyway - but it does mean playing near exposed
live parts since you will need to take the front off the CU to change it).

You could however just label it carefully and use a lower rating of fuse
wire.

Thanks - that is what I will do. It will also make me get a card of
fuse wire for my daughter's house as I threw mine away 20 years ago
when I moved and got a cartridge fuse consumer unit. You never know
when you will need it.

Interestingly, the cooker has two ovens with ratings of 2.4/2.7 Kw
and 1.8/2.0 Kw at 230/240 V and specifies 4mm cable for connection. It
then specifies it should be fused at 13A, which seems a bit light to
me!

You normally apply diversity to the calculation for a domestic cooker.
This is 10A + 30% of the remainder of the total load (assuming no socket
on the cooker point - add a further 5A for a socket).

So in your case the total load is 4.2kW or 18.26A
So that gives you 10A + (18.26 - 10) * 0.3 = 12.48A

You can get away with this because the load is thermostatically
controlled, so once the element is up to temperature the stat will be
cycling the power, thus giving a lower overall average. The
instantaneous peak current is less important since it takes time to heat
a cable to a point where it would be damaged, and so its temperature
will tend to reflect the average load on it rather than the peak.




--
Cheers,

John.

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

In article
,
JohnW wrote:
I have a Wylex Consumer unit with rewireable fuses. The cooker fuse is
30A (Red) which I need to change to 15A (Blue). Do I have to change the
backplate as well as the fuse, as the cable is still rated at 30A so the
30A fuse could safely be reinstated for a future appliance (6mm cable).
I just want to fuse the current cooker with a lower value as it has a
gas hob. So the question is - is putting a 15A fuse in a 30A fuseway
against any regs?

It would be confusing since the colours wouldn't be the same.

But unless I'm missing something it's not a backplate and merely a cover
held on by one screw - and can be changed in seconds.

--
*My dog can lick anyone

Dave Plowman London SW
To e-mail, change noise into sound.

"JohnW" wrote in message
...
The 15A fuse former[1] (blue dots) won't fit the 30A backplate - so to
actually change it would require you change the back bit as well (they
usually come as a set anyway - but it does mean playing near exposed
live parts since you will need to take the front off the CU to change it).

You could however just label it carefully and use a lower rating of fuse
wire.

Thanks - that is what I will do. It will also make me get a card of
fuse wire for my daughter's house as I threw mine away 20 years ago
when I moved and got a cartridge fuse consumer unit. You never know
when you will need it.

Interestingly, the cooker has two ovens with ratings of 2.4/2.7 Kw
and 1.8/2.0 Kw at 230/240 V and specifies 4mm cable for connection. It
then specifies it should be fused at 13A, which seems a bit light to
me!

John

If the specification is for 13A then swap the cooker outlet plate if you
have one for a switched fused spur with a 13A fuse and leave the Wylex fuse
at 30A.

What make and model is the cooker? Asking for 4mm connection cable sounds a
little like overkill.

Adam

"Frank Erskine" wrote in message
...
On Mon, 15 Dec 2008 16:00:19 +0000, John Rumm
wrote:




You don't actually need to take the front off the CU - all you do is
(carefully) remove the single fixing screw for the backplate and lift
it out.
Refitting is the reverse of the above - but be careful as the busbar
behind is live and it's easy to catch the screw on it.

--
Frank Erskine


Too true, and to make it worse the screw is closer to the busbar than it is
to the outgoing "dead" terminal at the top. Add the massive amount of play
in the screw and it is easy to get caught out.

Adam

On Mon, 15 Dec 2008 06:49:57 -0800 (PST), JohnW
wrote:

I have a Wylex Consumer unit with rewireable fuses. The cooker fuse is
30A (Red) which I need to change to 15A (Blue). Do I have to change
the backplate as well as the fuse, as the cable is still rated at 30A
so the 30A fuse could safely be reinstated for a future appliance (6mm
cable).

What do you really think the consumer unit fuse / MCB is protecting?
It's almost never ever the appliance, it's the cable.

Leave the 30A fuse in there with the existing cable and even if you
installed a cooker with no heating elements and just a 15W light in
the oven space then your installation is safe and adequately
protected.


--

John Rumm wrote:

If in doubt, turn off the main switch - then the only live bit is still
under cover (unless you are right up against the switch end, where if
memory serves, you may be able to poke something into the metalwork near
the top of the switch).

Interesting point, and with the common practice of populating CUs starting
with the highest rated fuseways closest to the main switch that could be
quite likely in this case.

--
Mike Clarke

"Mike" wrote in message
...
On Mon, 15 Dec 2008 06:49:57 -0800 (PST), JohnW
wrote:

I have a Wylex Consumer unit with rewireable fuses. The cooker fuse is
30A (Red) which I need to change to 15A (Blue). Do I have to change
the backplate as well as the fuse, as the cable is still rated at 30A
so the 30A fuse could safely be reinstated for a future appliance (6mm
cable).

What do you really think the consumer unit fuse / MCB is protecting?
It's almost never ever the appliance, it's the cable.

Leave the 30A fuse in there with the existing cable and even if you
installed a cooker with no heating elements and just a 15W light in
the oven space then your installation is safe and adequately
protected.


That sounds about as safe as letting Gary Glitter babysit the kids with
Micheal Jackson supplying the entertainment and Beverley Allitt acting as
the nursemaid with Sharon Shoesmith overseeing it all in case things go
wrong.

Adam

In article , John Rumm
writes

The 15A fuse former[1] (blue dots) won't fit the 30A backplate

It's dark out and I'm not about to start farting about with my fusebox,
but I seem to remember that lower-rated fuses will fit the higher-rated
backplates (so you could put a 5A fuse into a 15A backplate for example)
but not vice versa.

Actually, I've just had a play with my stock of Wylex rewirable spares.
There seem to be two different types of backplate - recessed and flush.
A 5A fuse will plug into a recessed 30A backplate, but not a flush 30A
backplate.

--
(\__/)
(='.'=) Bunny says Windows 7 is Vi$ta reloaded.
(")_(")

On Mon, 15 Dec 2008 20:20:51 GMT, "ARWadsworth"
wrote:


"Mike" wrote in message
.. .
On Mon, 15 Dec 2008 06:49:57 -0800 (PST), JohnW
wrote:

I have a Wylex Consumer unit with rewireable fuses. The cooker fuse is
30A (Red) which I need to change to 15A (Blue). Do I have to change
the backplate as well as the fuse, as the cable is still rated at 30A
so the 30A fuse could safely be reinstated for a future appliance (6mm
cable).

What do you really think the consumer unit fuse / MCB is protecting?
It's almost never ever the appliance, it's the cable.

Leave the 30A fuse in there with the existing cable and even if you
installed a cooker with no heating elements and just a 15W light in
the oven space then your installation is safe and adequately
protected.


That sounds about as safe as letting Gary Glitter babysit the kids with
Micheal Jackson supplying the entertainment and Beverley Allitt acting as
the nursemaid with Sharon Shoesmith overseeing it all in case things go
wrong.

But it is completely safe. Do you suddenly decide to fit a smaller
MCB or fuse on a ring main when because of the credit crunch you stop
using a 3 bar electric fire to keep warm and sit instead round a 15W
candle lamp plugged into a 13A socket outlet for warmth?

The plug fuse protects the cable to the lamp, the fuse or MCB at the
consumer unit protects the fixed wiring.

A 30A fuse or MCB fitted in a consumer unit, on a circuit such as a
cooker circuit using cable originally sized for carrying that load is
safe with a load of 30A (and beyond) or without any load or with any
load between those values.

What if you fit a gas cooker and for some ambient lighting in the
kitchen you plug a able lamp into the socket on the cooker outlet
unit. Does that installation, fuse/MCB cable etc suddenly become
unsafe? (assume the lampshade is nowhere near the gas flame!)

For f*cks sake calling someone to back me up on this! Am I right or
am I completely mad?




--

In article ,
John Rumm wrote:
The 15A fuse former[1] (blue dots) won't fit the 30A backplate - so to
actually change it would require you change the back bit as well (they
usually come as a set anyway - but it does mean playing near exposed
live parts since you will need to take the front off the CU to change it).

Are you sure, John? I thought the only difference apart from the colour
was the size of the holes for the fuse carrier pins - so a 'smaller'
carrier would fit, but not a larger one.

--
*Drugs may lead to nowhere, but at least it's the scenic route *

Dave Plowman London SW
To e-mail, change noise into sound.

On Tue, 16 Dec 2008 00:30:20 +0000, Mike wrote:


But it is completely safe. Do you suddenly decide to fit a smaller
MCB or fuse on a ring main when because of the credit crunch you stop
using a 3 bar electric fire to keep warm and sit instead round a 15W
candle lamp plugged into a 13A socket outlet for warmth?

What's that to do with 'credit crunch'?

Is that a sort of breakfast cereal?

Am I right or
am I completely mad?

I think we're all (fsvo) mad.

--
Frank Erskine

What make and model is the cooker? Asking for 4mm connection cable sounds a
little like overkill.

Adam

It is a Hotpoint EG74 Dual Fuel. I did assume when it asked for 4mm
it would be fused at 30 A, but the book says 13 A.


John

On Mon, 15 Dec 2008 23:16:21 -0800 (PST), JohnW
wrote:

What make and model is the cooker? Asking for 4mm connection cable sounds a
little like overkill.


It is a Hotpoint EG74 Dual Fuel. I did assume when it asked for 4mm
it would be fused at 30 A, but the book says 13 A.

Since WHEN have appliance manufacturers dictated FIXED WIRING
STANDARDS?

If they said 1.0mm rubber and lead cable, and a 5A rewireable fuse
would you hack out the wall, run a new cable and rip out a brand new
17th edition consumer unit so you could fit a 1950's wooden one bought
from the antiques section on Ebay?

If not then why would you change the correctly designed electrical
protection of a perfectly serviceable 6mm cable on the whim of an
appliance manufacturer? By some of the ridiculous responses in here I
suspect a few would!


--

On Tue, 16 Dec 2008 00:44:24 +0000, Frank Erskine
wrote:

On Tue, 16 Dec 2008 00:30:20 +0000, Mike wrote:


But it is completely safe. Do you suddenly decide to fit a smaller
MCB or fuse on a ring main when because of the credit crunch you stop
using a 3 bar electric fire to keep warm and sit instead round a 15W
candle lamp plugged into a 13A socket outlet for warmth?

What's that to do with 'credit crunch'?

Downsizing from a 3 bar electric fire to keep warm to a 15W candle
lamp. Guaranteed cost savings of 99.5% and usable light so you can
while away the hours reading the 17th edition regs dreaming of the
day you can fleece customers for Prat P inspections.

Is that a sort of breakfast cereal?

You expect to eat too? This is a credit crunch not a free lunch.

Am I right or
am I completely mad?

I think we're all (fsvo) mad.

That's ok then.


--

Dave Plowman (News) wrote:
In article ,
John Rumm wrote:
The 15A fuse former[1] (blue dots) won't fit the 30A backplate - so to
actually change it would require you change the back bit as well (they
usually come as a set anyway - but it does mean playing near exposed
live parts since you will need to take the front off the CU to change it).

Are you sure, John? I thought the only difference apart from the colour
was the size of the holes for the fuse carrier pins - so a 'smaller'
carrier would fit, but not a larger one.

I don't have one here to play with, so can't say for certain (and
swapping fuse carriers about is not something I would usually do as a
matter of routine). I *am* sure you can't fit a bigger carrier into a
smaller backplate - but I can't remember for sure if the reverse is also
true. I would be less inclined to use the wrong carrier / back plate
combination though as it will be harder to understand for someone coming
along later.

--
Cheers,

John.

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

In article , writes

Aren't the recessed ones for rewirable fuses and the flush ones for
MCB/cartridge fuses? Different spacing to prevent fitting the wrong type.

Yes, that seems to jog my memory.

--
(\__/)
(='.'=) Bunny says Windows 7 is Vi$ta reloaded.
(")_(")

It is a Hotpoint EG74 Dual Fuel. *I did assume when it asked for 4mm
it would be fused at 30 A, but the book says 13 A.

Since WHEN have appliance manufacturers dictated FIXED WIRING
STANDARDS?


Sorry - a misunderstanding - the 4mm cable is specified to be used
from the fixed wiring (i.e. the cooker point connector box) to the
appliance.

John

"Owain" wrote in message
...
JohnW wrote:
What make and model is the cooker? Asking for 4mm connection cable
sounds a
little like overkill.
It is a Hotpoint EG74 Dual Fuel. I did assume when it asked for 4mm
it would be fused at 30 A, but the book says 13 A.

A lot of ovens are under 13A - it's the hobs that take the current, and
I assume that's gas.

Easy answer is to leave your circuit arrangements as they are and put a
13A FCU near the cooker if you are worried.

Owain


I suspect that the 13A fuse is a misprint. The manual is below

http://imagebank.indesitcompany.co.u...tpoint/Cooking
/EG74_19505756000.pdf


Although the grill cannot operate with the top oven, using the main oven and
the grill together gives 4.2kW at 230V. A 20 amp fuse or MCB would probably
be the best solution.

Adam

"Mike" wrote in message
...
On Mon, 15 Dec 2008 20:20:51 GMT, "ARWadsworth"
wrote:


"Mike" wrote in message
.. .
On Mon, 15 Dec 2008 06:49:57 -0800 (PST), JohnW
wrote:

I have a Wylex Consumer unit with rewireable fuses. The cooker fuse is
30A (Red) which I need to change to 15A (Blue). Do I have to change
the backplate as well as the fuse, as the cable is still rated at 30A
so the 30A fuse could safely be reinstated for a future appliance (6mm
cable).

What do you really think the consumer unit fuse / MCB is protecting?
It's almost never ever the appliance, it's the cable.

Leave the 30A fuse in there with the existing cable and even if you
installed a cooker with no heating elements and just a 15W light in
the oven space then your installation is safe and adequately
protected.


That sounds about as safe as letting Gary Glitter babysit the kids with
Micheal Jackson supplying the entertainment and Beverley Allitt acting as
the nursemaid with Sharon Shoesmith overseeing it all in case things go
wrong.

But it is completely safe. Do you suddenly decide to fit a smaller
MCB or fuse on a ring main when because of the credit crunch you stop
using a 3 bar electric fire to keep warm and sit instead round a 15W
candle lamp plugged into a 13A socket outlet for warmth?

The plug fuse protects the cable to the lamp, the fuse or MCB at the
consumer unit protects the fixed wiring.

A 30A fuse or MCB fitted in a consumer unit, on a circuit such as a
cooker circuit using cable originally sized for carrying that load is
safe with a load of 30A (and beyond) or without any load or with any
load between those values.

What if you fit a gas cooker and for some ambient lighting in the
kitchen you plug a able lamp into the socket on the cooker outlet
unit. Does that installation, fuse/MCB cable etc suddenly become
unsafe? (assume the lampshade is nowhere near the gas flame!)

For f*cks sake calling someone to back me up on this! Am I right or
am I completely mad?


Mike

You have added an extra socket and fused plug to your reply that was not on
your original post:-)

There is nothing wrong with a 30 amp fuse supplying 6mm T&E to a single
socket and then using the single socket to supply a 15W light using a 3A
plug or something similar.

I knew what you meant on your OP but you did not say it. I am frequently
guilty of doing that as well.

Adam