Can i use a 13A plug for a 3.6kW connected load combi microwave oven?

[EFLImpudence]

That relates to the ring final. It does not say they cannot be supplied by a radial with higher rating OPDs.

 

[stillp]

I agree.

 

[chivers67]

The double socket is connected to a separate fuse ; a Wylex B40 MCB via a thick cable

Think it might help if you find out the rating of said Thick cable in the first instance

 

[JohnW2]

However, 433.1.103 states "Accessories to BS1363 may be supplied through a ring final circuit, with or without unfused spurs, protected by a 30 A or 32 A protective device complying with..."

It does, but we're talking about a (presumably) radial cooker circuit, not a ring final!

Kind Regards, John

 

[stillp]

But we're talking of a BS1363 socket-outlet!

 

[JohnW2]

But we're talking of a BS1363 socket-outlet!

We are, but the BS7671 regulation about ring finals does not really help us in relation to a BS1363 socket on a radial!

Are you able to tell us what BS1363 actually says (if anything) about what 'through' currents the terminals of a socket-outlet have to be able to carry and/or what it says (if anything) about potential currents in the circuit to which it is connected? [I think you have already more-or-less answered the latter]

Kind Regards, John

 

[EFLImpudence]

433.1.103 is the requirements for a ring final; not the BS1363 accessories.

It says they may (not may only) be supplied by this arrangement - a particular peculiarly allowed circuit; it does nor preclude other arrangements - other circuits.

 

[perm d]

Many thanks for all the input folks . It is highly unlikely that we will use all of the functions on the new oven at the same time but then one never knows !
The appliances have worked without problems and the fuse never tripped . I will get an electrician to check but i thought either leave the 13A socket as is , and take a spur and wire the new appliance with the 'advised ' 16A plug or alternatively , taking future plans into account replace the socket with a double socket 16A each ? but might be over-kill of sorts ?
The main oven rated at 2.8kW has only been used approx 30 times in 10 years and looks as new ! , so no point to replace it .
Around 3 months after the rewiring and connection of appliances , i had an electrician evaluate the safety and correctness of the wiring /fuses throughout the house and after some advisories regarding lighting which he then fixed , and then gave me a NCIEC ? electrical certificate .

 

[stillp]

Are you able to tell us what BS1363 actually says (if anything) about what 'through' currents the terminals of a socket-outlet have to be able to carry and/or what it says (if anything) about potential currents in the circuit to which it is connected? [I think you have already more-or-less answered the latter]

I have indeed answered the latter. Can you explain what effect, if any, you think the current in two conductors connected within the same terminal would have on the accessory of which that terminal was a part?

 

[JohnW2]

I have indeed answered the latter. Can you explain what effect, if any, you think the current in two conductors connected within the same terminal would have on the accessory of which that terminal was a part?

That's easy - I do not believe (within reason!) that the current in those conductors would have any appreciable (if any) effect on the accessory. However this is something that people always seem to be get excited about - for example, when have a "20A switch" {often a grid switch} supplying a single 13A socket is wired in a ring final - although, admittedly, there is then also the technicality that the switch will not be 'an accessory to BS1363'.

Kind Regards, John

 

[stillp]

I usually tell people to imagine that the conductor in each terminal was not joined, but a continuous loop. That seems to make it easier to realise that the current in the conductor doesn't have to flow in the accessory.
There will of course be a slight heating effect in the cable, which will affect the heat flow away from the accessory, but the effect is negligible.

 

[stillp]

replace the socket with a double socket 16A each ?

You'll struggle to find one of those.

 

[JohnW2]

I usually tell people to imagine that the conductor in each terminal was not joined, but a continuous loop. That seems to make it easier to realise that the current in the conductor doesn't have to flow in the accessory. There will of course be a slight heating effect in the cable, which will affect the heat flow away from the accessory, but the effect is negligible.

I agree totally, but you will not have to monitor this forum for too long to see people 'getting excited' about the current flowing between two conductors in the terminal of an accessory! It all seems to come down to their perception of what "the current rating" of an accessory means.

Of course, even if it were a continuous conductor, some (probably a tiny proportion) of the current flowing between the 'incoming' and 'outgoing' parts of the conductor would flow through the material of the terminal (as a 'parallel path') - but I am sure that (as well as the thermal effects you mention) would be negligible.

Kind Regards, John

 

[sparkwright]

We haven't really reached a satisfactory conclusion to this.

Can you apply diversity to this and use a 13 amp plug?

It's been observed that anything over 2.5 kW shouldn't really have a 13 amp plug, though I think it's a bit of grey area.

I would say hardwiring is better.

What do the manufacturers instructions state? It's very likely they would stipulate 16 amp protection.

If so, would we take any notice of that?

 

[sparkwright]

Based on the fact a 13 amp plug with a 3 kW load can melt easily, I would say not fit a 13 amp plug on this 3.6 kW appliance - diversity or no diversity.