Is this ok?

[dantheram]

No probs

 

[dantheram]

 

[flameport]

I am considering adding a 13a FCU before the socket supplying the washer then running on to the underfloor heating. Total possible draw will be 3050w on 13a socket.

No problem with that.
Ring/radial or whatever is irrelevant.

 

[JohnW2]

I am considering adding a 13a FCU before the socket supplying the washer then running on to the underfloor heating. Total possible draw will be 3050w on 13a socket.

No problem with that. Ring/radial or whatever is irrelevant.

Ah - you've obviously interpreted what the OP wrote differently from the rest of us - but, on reflection, you could well be right. I (and I presume others) was taking the intention to be to 'spur off' to an FCU from the existing socket (which now appears to be an unfused sour from a ring final), rather than to have both the socket and the UFH on the load side of an FCU. As you say, the latter would be (just about, in max load terms) OK.

Kind Regards, John

 

[Iggifer]

and ahhh ye olde MK MCBs

 

[dantheram]

Here is the intention -

Wall socket with 3 cables (ring final) - - - - FCU 13a switched - - - - double socket - - - - UFH

Load as I said would only ever be 3050w max. 13a will give 3120w, so just inside the max.

It is a spur off a spur but as the FCU is going in supply side before the first socket it is ok.

Correct?

 

[JohnW2]

Here is the intention - Wall socket with 3 cables (ring final) - - - - FCU 13a switched - - - - double socket - - - - UFH

Thanks, and apologies for having misunderstood. On reflection, what you wrote was pretty clear, but I (and others) didn't take it in properly.

Load as I said would only ever be 3050w max. 13a will give 3120w, so just inside the max.

Indeed (assuming the powers of the loads were quoted at 240V - which they probably were).

It is a spur off a spur but as the FCU is going in supply side before the first socket it is ok. Correct?

Yes, it's OK. In fact, with the 'up-front' FCU, it would not usually be described as a 'spur off a spur' - but, rather, just as a 'fused spur' (which could, for example, have an unlimited number of sockets connected to it). It is 'spurs off unfused spurs' which is not allowed (i.e. an 'unfused spur' can only supply one socket (or FCU), and nothing more).

I still don't think it's ideal for you to have all the sockets in your house and the UFH all running off one 30A circuit. However, that is not non-compliant with regulations if it is felt that the total load is unlikely to exceed 30A for appreciable periods.

Kind Regards, John

 

[dantheram]

Here is the intention - Wall socket with 3 cables (ring final) - - - - FCU 13a switched - - - - double socket - - - - UFH

Thanks, and apologies for having misunderstood. On reflection, what you wrote was pretty clear, but I (and others) didn't take it in properly.

Load as I said would only ever be 3050w max. 13a will give 3120w, so just inside the max.

Indeed (assuming the powers of the loads were quoted at 240V - which they probably were).

It is a spur off a spur but as the FCU is going in supply side before the first socket it is ok. Correct?

Yes, it's OK. In fact, with the 'up-front' FCU, it would not usually be described as a 'spur off a spur' - but, rather, just as a 'fused spur' (which could, for example, have an unlimited number of sockets connected to it). It is 'spurs off unfused spurs' which is not allowed (i.e. an 'unfused spur' can only supply one socket (or FCU), and nothing more).

I still don't think it's ideal for you to have all the sockets in your house and the UFH all running off one 30A circuit. However, that is not non-compliant with regulations if it is felt that the total load is unlikely to exceed 30A for appreciable periods.

Kind Regards, John

Thanks for the input, John.

I do agree that it's no ideal for everything to be on that 30a circuit, but I don't envisage running at that level very often. It's a small 2 bed semi with 2 occupants but appliances soon add up I guess.

Dan

 

[JohnW2]

Thanks for the input, John. ... I do agree that it's no ideal for everything to be on that 30a circuit, but I don't envisage running at that level very often. It's a small 2 bed semi with 2 occupants but appliances soon add up I guess.

You're welcome ... but, yes, things do quickly add up. Don't forget that it takes only three 'high powered' appliances (washing machine, dryer, dishwasher, kettle, toaster, fan heater etc.) to be on simultaneously to get you pretty close to 30A. The saving grace is that there are lot of 'safety margins' built into everything we do, such that to go appreciably over 30A (on a 30A circuit) for a relatively short period of time is not going to be dangerous or do any harm - even though it would be 'bad design' (hence theoretical non-compliance with regs) to have a circuit in which that was considered 'likely' to happen.

Kind Regards, John

 

[dantheram]

Thanks for the input, John. ... I do agree that it's no ideal for everything to be on that 30a circuit, but I don't envisage running at that level very often. It's a small 2 bed semi with 2 occupants but appliances soon add up I guess.

You're welcome ... but, yes, things do quickly add up. Don't forget that it takes only three 'high powered' appliances (washing machine, dryer, dishwasher, kettle, toaster, fan heater etc.) to be on simultaneously to get you pretty close to 30A. The saving grace is that there are lot of 'safety margins' built into everything we do, such that to go appreciably over 30A (on a 30A circuit) for a relatively short period of time is not going to be dangerous or do any harm - even though it would be 'bad design' (hence theoretical non-compliance with regs) to have a circuit in which that was considered 'likely' to happen.

Kind Regards, John

My big draws are washer, Hoover, kettle, microwave and fridge freezer. Everything else is small fry in comparison

 

[JohnW2]

My big draws are washer, Hoover, kettle, microwave and fridge freezer. Everything else is small fry in comparison

Fair enough. If that's all, if you had them on all together (plus all the small fry), you'd probably still be appreciably short of 30A.

Kind Regards, John

 

[dantheram]

Thanks everyone who chipped in, much appreciated.

 

[syl]

Assuming you can plug in underfloor heating, you could even switch the single plug socket for a dual outlet, which is usually good for 20A. You could use a 5A fuse in the plug.