replacing old fuses with mcb switches on old style board

[dogwood_chris]

we have recently moved into a property with the old style wylex consumer unit with wired fuses. As i am planning to do various bits of diy i wanted to be able to switch off individual circuits at various times so i thought i would replace the old wired fuses with mcb's that seem available for cheap on ebay.

house is 2 bed with around half a dozen sockets per ring main and 3 lighting roses per floor

the consumer unit has a 60amp trip switch between it and the meter

the board itself has 2, 5amp fuses, for upstairs and downstairs radial lighting circuits,

3 ring main cirucits (upstairs downstairs and 70's kitchen extension)
and a 30 amp fuse for cooker socket.

what size should i replace them with-? when I've looked, the mcbs come in 6amp(presumably to replace 5amp radial)16,20,30,32,40 etc

however, of the 3 ring mains fuses, one has already been replaced by a 40amp mcb and the two remaining have 15A printed on the fuse holder? should i replace these with 16A mcbs or can i replace them with 30A or even 40A mcbs(like the one already there)

i'm confused as to why the old fuses are rated as 15A as i thought you chad 30 A on a ring main?

thanks in advance

 

[EFLImpudence]

we have recently moved into a property with the old style wylex consumer unit with wired fuses. As i am planning to do various bits of diy i wanted to be able to switch off individual circuits at various times so i thought i would replace the old wired fuses with mcb's that seem available for cheap on ebay.

You can remove the fuse. It should have no load on it when you do.

the consumer unit has a 60amp trip switch between it and the meter

Do you mean just a switch?

5A to 6A
15A to 16A
30A to 32A

however, of the 3 ring mains fuses, one has already been replaced by a 40amp mcb

Are you sure this is not a cooker or a shower.
I have no way of telling if this is appropriate.

and the two remaining have 15A printed on the fuse holder? should i replace these with 16A mcbs

Yes.

or can i replace them with 30A or even 40A mcbs(like the one already there)

NO. Why would you want to?

i'm confused as to why the old fuses are rated as 15A as i thought you had 30 A on a ring main?

Immersion heater? Storage heater?

 

[dogwood_chris]

thanks for your post mate, i will get the corresponding mcbs

i just preferred flicking switches than to keep removing the old fuses and i thought it would be easier than replacing blown fuses when appropriate

firstly, the switch between meter and consumer unit is a 'earth leakage circuit breaker,' it has an off/on position and a yellow bar 'tester'



the circuit with the 40amp mcb is the upstairs ring main, . it also by the looks of it may have had an immersion heater that was later disconnected. is this why it would be 40a?
there is an upstairs electric shower that doesn't have its own circuit. i forgot to check this when testing what sockets/lights belong to which fuse.could this ne part of the upstairs ring main and a reason for the 40 a mcb

the rest makes sense

thanks

 

[JohnW2]

firstly, the switch between meter and consumer unit is a 'earth leakage circuit breaker,' it has an off/on position and a yellow bar 'tester'
the circuit with the 40amp mcb is the upstairs ring main, . it also by the looks of it may have had an immersion heater that was later disconnected. is this why it would be 40a?
there is an upstairs electric shower that doesn't have its own circuit. i forgot to check this when testing what sockets/lights belong to which fuse.could this ne part of the upstairs ring main and a reason for the 40 a mcb

I know it's not what you want to hear, but there are several things in what you've just written which suggest a fairly urgent need to get an electrician to look over your electrical installation and give you some advice.

Kind Regards, John

 

[dogwood_chris]

firstly, the switch between meter and consumer unit is a 'earth leakage circuit breaker,' it has an off/on position and a yellow bar 'tester'
the circuit with the 40amp mcb is the upstairs ring main, . it also by the looks of it may have had an immersion heater that was later disconnected. is this why it would be 40a?
there is an upstairs electric shower that doesn't have its own circuit. i forgot to check this when testing what sockets/lights belong to which fuse.could this ne part of the upstairs ring main and a reason for the 40 a mcb

I know it's not what you want to hear, but there are several things in what you've just written which suggest a fairly urgent need to get an electrician to look over your electrical installation and give you some advice.

Kind Regards, John

yes, i think that may be well in order to be honest, thanks

 

[EFLImpudence]

firstly, the switch between meter and consumer unit is a 'earth leakage circuit breaker,' it has an off/on position and a yellow bar 'tester'

Ok. Is it a modern one?

the circuit with the 40amp mcb is the upstairs ring main, . it also by the looks of it may have had an immersion heater that was later disconnected. is this why it would be 40a?

No. It must not be 40A for a ring circuit.

there is an upstairs electric shower that doesn't have its own circuit. i forgot to check this when testing what sockets/lights belong to which fuse.could this ne part of the upstairs ring main and a reason for the 40 a mcb

It would appear to have been meddled with by someone who did not know what they were doing.
Showers should be on their own circuit.
I would suggest you have it inspected by an electrician.

 

[flameport]

i will get the corresponding mcbs

Those things are a waste of money. They offer no advantages over the fuses you have already got.
Ebay is not a suitable place to purchase electrical items designed to prevent your house from burning to the ground..

i just preferred flicking switches than to keep removing the old fuses and i thought it would be easier than replacing blown fuses when appropriate

Fuses should not need replacing. If they do, there is something wrong with the installation.

firstly, the switch between meter and consumer unit is a 'earth leakage circuit breaker,' it has an off/on position and a yellow bar 'tester'

One of these? http://www.flameport.com/electric_museum/old_elcb/chilton_elcb.cs4
If so, it should have been replaced decades ago.

the circuit with the 40amp mcb is the upstairs ring main,
there is an upstairs electric shower that doesn't have its own circuit.

All bad news. It's fairly likely that the fusebox isn't suitable for 40A devices, and even if it is, an electric shower must have it's own circuit.

Rather than spending money on useless plug in MCBs, get someone in to assess the installation and find out just how bad it actually is. Then upgrade/replace as necessary.