Normally I'd be more than happy to offer advise if adequate information is supplied. You seem to have a fairly good grip on the situation but in this case there seems to be far too many doubts, sorry to say it bit I think this needs the attendance of an electrician to inspect and assess.
Change of electrics required for new oven?
- Thread starter Dave123456789
- Start date
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I’ve had a few napit guys in for quotes 
From consumer unit - there’s a 32 amp break for oven - radial circuit 2.5mm cable
Been told to change this to 16 amp
The tests showed the oven has its own radial socket
I can buy a 3/3.2 kw single electric oven and have this on current circuit
(Get gas guy to cap off existing double gas oven)
Kitchen socket are on a ring also 2.5mm cable
I can spur off a socket with fcu and fit my microwave either by socket plug or hard wire
It’ll be on kitchen ring so not ideal but just gotta make a note
As best practice also been told that where the two 2.5mm wires join onto a 4mm cable
Split these up directly into consumer unit
Last person prob ran out of cable
Happy days
From consumer unit - there’s a 32 amp break for oven - radial circuit 2.5mm cable
Been told to change this to 16 amp
The tests showed the oven has its own radial socket
I can buy a 3/3.2 kw single electric oven and have this on current circuit
(Get gas guy to cap off existing double gas oven)
Kitchen socket are on a ring also 2.5mm cable
I can spur off a socket with fcu and fit my microwave either by socket plug or hard wire
It’ll be on kitchen ring so not ideal but just gotta make a note
As best practice also been told that where the two 2.5mm wires join onto a 4mm cable
Split these up directly into consumer unit
Last person prob ran out of cable
Happy days
So to summarise
It will go like this
16amp breaker for oven radial circuit 2.5mm cabling
For single eclectic oven
(Disconnect her double gas oven)
32amp breaker for kitchen ring sockets circuit 2.5mm cabling
For dishwasher gas hob washing machine dryer toaster kettle - and plus microwave will go into a single socket or fcu spurred off one of these sockets for power
It will go like this
16amp breaker for oven radial circuit 2.5mm cabling
For single eclectic oven
(Disconnect her double gas oven)
32amp breaker for kitchen ring sockets circuit 2.5mm cabling
For dishwasher gas hob washing machine dryer toaster kettle - and plus microwave will go into a single socket or fcu spurred off one of these sockets for power
For a radial circuit wired in 2.5mm², you can have a 20A or a 25A MCB.
A 16A breaker will limit your options.
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They are right in one sense
A 32A is not right for this set up
BUT
2.5mm cable is rated at 27A when it’s installed properly. So they can provide the rating that is equal to, or smaller than 27A.
Some CU makers do a 25A breaker, 20A is more common.
Why did they specify 16A? Does that happen to be the value that they’ve got on the van?
A 32A is not right for this set up
BUT
2.5mm cable is rated at 27A when it’s installed properly. So they can provide the rating that is equal to, or smaller than 27A.
Some CU makers do a 25A breaker, 20A is more common.
Why did they specify 16A? Does that happen to be the value that they’ve got on the van?
Correct.
20a are easily available and be more useful.
25a may not be available for your brand of consumer unit
20a are easily available and be more useful.
25a may not be available for your brand of consumer unit
He said:
Im pretty sure that MK don’t make a 25A MCB for your consumer unit.
A 20A would be fine for the cable fitted, but combined with the start up currents and running loads of both your microwave and oven, it would lead to a lot of nuisance tripping if you had both appliances in use, especially as the microwave starts up when you press the start button.
To avoid this, you are better off sticking with a 16A MCB for the oven circuit, and then having the FCU or single socket spur’d from the double socket in the utility area to provide power for your microwave.
There’s no reason you couldn’t have the 20A MCB for your oven circuit, it just isn’t necessary, and there’s really no point over providing for a circuit if you don’t need to.
Hope that helps.
Sounds fair?
Im pretty sure that MK don’t make a 25A MCB for your consumer unit.
A 20A would be fine for the cable fitted, but combined with the start up currents and running loads of both your microwave and oven, it would lead to a lot of nuisance tripping if you had both appliances in use, especially as the microwave starts up when you press the start button.
To avoid this, you are better off sticking with a 16A MCB for the oven circuit, and then having the FCU or single socket spur’d from the double socket in the utility area to provide power for your microwave.
There’s no reason you couldn’t have the 20A MCB for your oven circuit, it just isn’t necessary, and there’s really no point over providing for a circuit if you don’t need to.
Hope that helps.
Sounds fair?
sure that could work. Happy to be corrected on parts available. However, having just checked the cable ratings for twin and earth cable, 2.5mm, installed in a cavity wall (assuming some sort of insulation also within) and the cable touching the inner surface of the cavity wall, ref method 102, the maximum current allowed for the cable would actually be 21A.
Without knowing the exact construction method of the walls containing the cable, it’s generally best to assume the worst case scenario and therefore avoid any potential issues in the future.
I appreciate trying to find the easiest and quickest possible way to solve the issue at hand but there are many variables at play.
I still stand by my suggestions as being the safest most reliable method given your current situation and the information available without opening up walls for further investigation etc...
The rating of 27A that you were given earlier is correct, but only when the cable is run clipped directly to the surface of a wall. Not the most attractive way of running a cable, and not the way that the cabling in question is run in your house to your utility/kitchen areas.
Regards
Fair points he makes....
Without knowing the exact construction method of the walls containing the cable, it’s generally best to assume the worst case scenario and therefore avoid any potential issues in the future.
I appreciate trying to find the easiest and quickest possible way to solve the issue at hand but there are many variables at play.
I still stand by my suggestions as being the safest most reliable method given your current situation and the information available without opening up walls for further investigation etc...
The rating of 27A that you were given earlier is correct, but only when the cable is run clipped directly to the surface of a wall. Not the most attractive way of running a cable, and not the way that the cabling in question is run in your house to your utility/kitchen areas.
Regards
Fair points he makes....
So is he going to fit a 20a rather than 16a now
Nope - 16 if I read it right
He’s seen the house tbf
Ie consumer unit
Travel of circuit
The rooms etc ..
He’s seen the house tbf
Ie consumer unit
Travel of circuit
The rooms etc ..
I believe he has given his answer in my post from 9.24pm sir...
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