Replacing Fuses with MCBs
 

Apologies for the lack of specifics here; I'm just at the stage of
finding out if this is feasible or not.

Currenly we have a traditional fusebox (fuses with fuse wire in ceramic
cylinder) installed and I wonder if it is possible to replace these
hoders with the circuit breaker type where a button pops out? Obviously
these things would have to be the same size and have the same fiitings.
Has anyone done this successfully or would I need a new fuse box?

My reason for asking is that every time one of the bulbs goes in my
kitchen light it takes out the fuse on the lighting circuit with it and
out go the downstairs lights. I'm getting a bit fed up of rewiring the
fuse.

Thanks

Tony

Replacing Fuses with MCBs
 

wrote in message
oups.com...
Apologies for the lack of specifics here; I'm just at the stage of
finding out if this is feasible or not.

Currenly we have a traditional fusebox (fuses with fuse wire in ceramic
cylinder) installed and I wonder if it is possible to replace these
hoders with the circuit breaker type where a button pops out? Obviously
these things would have to be the same size and have the same fiitings.
Has anyone done this successfully or would I need a new fuse box?

My reason for asking is that every time one of the bulbs goes in my
kitchen light it takes out the fuse on the lighting circuit with it and
out go the downstairs lights. I'm getting a bit fed up of rewiring the
fuse.

Thanks

Tony

providing the right type is available, then yes, no problem, I even found
some for a really ancient fuse board.

mrcheerful

Replacing Fuses with MCBs
 

wrote:

Currenly we have a traditional fusebox (fuses with fuse wire in ceramic
cylinder) installed and I wonder if it is possible to replace these
hoders with the circuit breaker type where a button pops out? Obviously
these things would have to be the same size and have the same fiitings.
Has anyone done this successfully or would I need a new fuse box?

If you have the traditional Wylex type rewireable fuses:

http://www.tlc-direct.co.uk/Main_Ind...ex_Rewireable/

Then you can get plug in MCBs to replace these:

http://www.tlc-direct.co.uk/Main_Ind...nge/index.html

Note that they are all "B" type MCBs. These are the "normal" type of MCB
that has a quite fast response to fault conditions. Hence they will trip
as often (in fact probably more often) in response to bulbs blowing than
the rewireable fuses you currently have. Saves replacing fuse wire but
still a PITA!

If you replaced the consumer unit with a more modern one then you could
use type C MCBs for the lighting circuits. This may reduce the number of
times you get spurious trips.


--
Cheers,

John.

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

Replacing Fuses with MCBs
 

"John Rumm" wrote in message
...
wrote:

Currenly we have a traditional fusebox (fuses with fuse wire in ceramic
cylinder) installed and I wonder if it is possible to replace these
hoders with the circuit breaker type where a button pops out? Obviously
these things would have to be the same size and have the same fiitings.
Has anyone done this successfully or would I need a new fuse box?

If you have the traditional Wylex type rewireable fuses:

http://www.tlc-direct.co.uk/Main_Ind...ex_Rewireable/

Then you can get plug in MCBs to replace these:

http://www.tlc-direct.co.uk/Main_Ind...nge/index.html

Note that they are all "B" type MCBs. These are the "normal" type of MCB
that has a quite fast response to fault conditions. Hence they will trip
as often (in fact probably more often) in response to bulbs blowing than
the rewireable fuses you currently have. Saves replacing fuse wire but
still a PITA!

If you replaced the consumer unit with a more modern one then you could
use type C MCBs for the lighting circuits. This may reduce the number of
times you get spurious trips.


--
Cheers,

John.

My fuse box has MEM stamped on the cover, would the Wylex type fit this or
is there an alternative.

thanks

Bill

Replacing Fuses with MCBs
 

John Rumm wrote:
If you have the traditional Wylex type rewireable fuses:

http://www.tlc-direct.co.uk/Main_Ind...ex_Rewireable/


Then you can get plug in MCBs to replace these:

http://www.tlc-direct.co.uk/Main_Ind...nge/index.html

Would such a replacement bring any safety benefit? My "new" (30 years
old) has such fuses instead of circuit breakers, and I'm worried about
the electrical safety of fuses vs circuit breakers.

Alex

Replacing Fuses with MCBs
 

On Tue, 1 Nov 2005 10:06:30 -0000 someone who may be "bill"
wrote this:-

My fuse box has MEM stamped on the cover, would the Wylex type fit this or
is there an alternative.

Probably not. http://www.memonline.com/uksales.html is the place to
start.





--
David Hansen, Edinburgh | PGP email preferred-key number F566DA0E
I will always explain revoked keys, unless the UK government
prevents me by using the RIP Act 2000.

Replacing Fuses with MCBs
 

On Tue, 01 Nov 2005 11:07:42 +0000 someone who may be Alex
wrote this:-

Would such a replacement bring any safety benefit? My "new" (30 years
old) has such fuses instead of circuit breakers, and I'm worried about
the electrical safety of fuses vs circuit breakers.

You need to split fuses into two, rewirable and cartridge fuses.

Cartridge fuses are moderately expensive, break high currents
rapidly and are moderately easy to replace.

Circuit breakers (of the sort we are talking about here) are the
most expensive, break moderate currents in time [1] and are easy to
reset.

Rewirable fuses are cheap, only break low currents and are fiddly to
replace.

For most houses circuit breakers are the most sensible form of
protective device. One of the few downsides is that, if the house is
near a substation, in some types of fault the circuit breaker will
fail to operate properly and the main (cartridge) fuse will operate.
Cartridge fuses guard against such problems, but cannot be reset.


[1] for many years now manufacturers have said that some of their
circuit breakers will break high currents as rapidly as a cartridge
fuse. However, the graphs they use to make these claims stop before
the interesting bits.


--
David Hansen, Edinburgh | PGP email preferred-key number F566DA0E
I will always explain revoked keys, unless the UK government
prevents me by using the RIP Act 2000.

Replacing Fuses with MCBs
 

On Tue, 01 Nov 2005 11:07:42 +0000, Alex
wrote:

John Rumm wrote:
If you have the traditional Wylex type rewireable fuses:

http://www.tlc-direct.co.uk/Main_Ind...ex_Rewireable/


Then you can get plug in MCBs to replace these:

http://www.tlc-direct.co.uk/Main_Ind...nge/index.html

Would such a replacement bring any safety benefit? My "new" (30 years
old) has such fuses instead of circuit breakers, and I'm worried about
the electrical safety of fuses vs circuit breakers.

There is no reason to assume that the fuses will be any less safe than
circuit breakers, assuming they were correctly installed in the first
place and have not been fiddled with.

The inherent problem with rewirable fuses is that you can rewire them
with just about anything. It is not uncommon to find that a fuse which
keeps blowing is "fixed" by putting in 30A wire instead of 5A. To a
lesser extent cartridge fuses can also be abused in this way.

The only case when I would definitely recommend replacing fuses with
MCBs on safety grounds is when the property is to be rented out, but
in such cases you would probably want to put in a split box anyway.

John
--
John White
SCA Electrical, Manchester http://www.scaelectrical.co.uk/
Domestic and commercial electrical contractors

Replacing Fuses with MCBs
 

"David Hansen" wrote in message
...
On Tue, 1 Nov 2005 10:06:30 -0000 someone who may be "bill"
wrote this:-

My fuse box has MEM stamped on the cover, would the Wylex type fit this or
is there an alternative.

Probably not. http://www.memonline.com/uksales.html is the place to
start.


Thanks for that - didn't know what MEM meant

Bill

Replacing Fuses with MCBs
 

David Hansen wrote:

Rewirable fuses have perfectly satisfactory breaking current ratings.

MCBs are prone to nuisance trips, fuses rarely are. If your fuse is
popping when the bulb goes, something isnt right. If you fit an mcb you
will have more nuisance trips, not less.

MCBs are generally reckoned to offer a bit more protection than fuses,
but its a fair bit less simple than that, and fuses have their plusses
too.

Its not usually necessary to go round replacing functioning fuses with
MCBs. If you want to worry about risks, getting hung up on trivia like
this is barking up the wrong tree. Your stairs are 100 times riskier.
Beds, roads, food, kitchens, power tools... not fuseboxes.

If youre using improperly ballotini fused bulbs and cant get decent
ones, a simple workaround is to put those lights on their own 3A fuse,
or better an mcb, between light fitting and CU. The 3A fuse is easily
replaced, or the mcb switched back on. Makes me wonder what kind of
bulbs youre using though.


NT

Replacing Fuses with MCBs
 

On 1 Nov 2005 08:58:06 -0800 someone who may be
wrote this:-

Rewirable fuses have perfectly satisfactory breaking current ratings.

That depends on what the short circuit current is at a particular
point in the particular installation.

Makes me wonder what kind of bulbs youre using though.

I think you mean someone else, not me.


--
David Hansen, Edinburgh | PGP email preferred-key number F566DA0E
I will always explain revoked keys, unless the UK government
prevents me by using the RIP Act 2000.

Replacing Fuses with MCBs
 

In article .com,
wrote:
My reason for asking is that every time one of the bulbs goes in my
kitchen light it takes out the fuse on the lighting circuit with it and
out go the downstairs lights. I'm getting a bit fed up of rewiring the
fuse.

Sounds like the circuit is running very close to its limit. Have you
calculated the maximum load?

--
*Money isn‘t everything, but it sure keeps the kids in touch

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

Replacing Fuses with MCBs
 

snip
Thanks for that - didn't know what MEM meant

Midland Electric Manufacturing (or similar). The company has been around
for about 90 years.

Replacing Fuses with MCBs
 

wrote:

MCBs are prone to nuisance trips, fuses rarely are. If your fuse is
popping when the bulb goes, something isnt right. If you fit an mcb you
will have more nuisance trips, not less.

Mains halogen bulbs seem to be the worst culprits here, but any filament
bulb can cause a current surge on failure if it manages to ionise the
gap between the feed wires at the end of the filament.

Its not usually necessary to go round replacing functioning fuses with
MCBs. If you want to worry about risks, getting hung up on trivia like
this is barking up the wrong tree. Your stairs are 100 times riskier.
Beds, roads, food, kitchens, power tools... not fuseboxes.

Adding RCD protection on appropriate circuits will probably make more
contribution to safety than just replacing fuses with MCBs. The MCBs
will obviously be more convenient should a trip occur.


--
Cheers,

John.

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

Replacing Fuses with MCBs
 

wrote:

MCBs are prone to nuisance trips, fuses rarely are. If your fuse is
popping when the bulb goes, something isnt right.

Any idea what might be going on? I reckon I'm not getting the lifetime
that I should be out of the bulbs in the fitting.

If you fit an mcb you will have more nuisance trips, not less.

I was think of something that was easier to reset when the fuse did
blow.

If youre using improperly ballotini fused bulbs and cant get decent
ones, a simple workaround is to put those lights on their own 3A fuse,
or better an mcb, between light fitting and CU. The 3A fuse is easily
replaced, or the mcb switched back on. Makes me wonder what kind of
bulbs youre using though.

It's the ceiling light in the kitchen. I've had two fittings; both
contained multiple spot bulbs. The older fitting held the screw-in
reflector type, the newer one holds four of the small spots that are
more popular now. With each fitting one of the bulbs would blow when
the light switched on and take the fuse with it.

Tony

Replacing Fuses with MCBs
 

Dave Plowman (News) wrote:
In article .com,
wrote:
My reason for asking is that every time one of the bulbs goes in my
kitchen light it takes out the fuse on the lighting circuit with it and
out go the downstairs lights. I'm getting a bit fed up of rewiring the
fuse.

Sounds like the circuit is running very close to its limit. Have you
calculated the maximum load?

No but I'd be surprised if it was at it's limit. The most recent
failure happened when no other downstairs lights were on. Unless
there's something hanging off the circuit that shouldn't be there, of
course.

Replacing Fuses with MCBs
 

On 1 Nov 2005 00:04:02 -0800, "
wrote:

Apologies for the lack of specifics here; I'm just at the stage of
finding out if this is feasible or not.

Currenly we have a traditional fusebox (fuses with fuse wire in ceramic
cylinder) installed and I wonder if it is possible to replace these
hoders with the circuit breaker type where a button pops out? Obviously
these things would have to be the same size and have the same fiitings.
Has anyone done this successfully or would I need a new fuse box?

My reason for asking is that every time one of the bulbs goes in my
kitchen light it takes out the fuse on the lighting circuit with it and
out go the downstairs lights. I'm getting a bit fed up of rewiring the
fuse.

Thanks

Tony

Tried from from Screwfix. Works fine but fuse box cover will not fit
-- MCB too proud.

Replacing Fuses with MCBs
 

wrote:

It's the ceiling light in the kitchen. I've had two fittings; both
contained multiple spot bulbs. The older fitting held the screw-in
reflector type,

These are usually ok...

the newer one holds four of the small spots that are
more popular now. With each fitting one of the bulbs would blow when
the light switched on and take the fuse with it.

These however are famous for poping bulbs and fuses at regular
intervals. They are also very sensitive to vibration - so someone
walking on the floor in the room above can be enough to shorten the life
of the bulbs a fair bit.

(the 12V halogen lights are much better in this respect since the
fillament runs at a much higher current and so needs to be thicker and
hence stronger. The light produced is also whiter and you get more of it)



--
Cheers,

John.

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

Replacing Fuses with MCBs