FCU query

[captaincoxman]

In my kitchen I have an FCU which has a twin socket coming off of it. The FCU is above the work surface and the twin is below it. We want to use the twin socket for a washing machine and tumble dryer (2 separate appliances) but I am cautious this may blow the 13a fuse in the FCU. Is it possible to replace the fuse in the FCU for a higher ampage or should I replace the FCU with a DP switch. I think both appliances will draw in the region of 2000w each...alternatively, is there a switch that could replace the twin and FCU...something that I could neatly label and control the power to each appliance? all my other sockets are MK electrics.

 

[ban-all-sheds]

In my kitchen I have an FCU which has a twin socket coming off of it. The FCU is above the work surface and the twin is below it.

Why is it on an FCU? Are there other sockets or appliances on the same spur, or is the FCU there solely to isolate the socket?

We want to use the twin socket for a washing machine and tumble dryer (2 separate appliances) but I am cautious this may blow the 13a fuse in the FCU.

It probably won't given the characteristics of BS1362 fuses, but it might.

Is it possible to replace the fuse in the FCU for a higher ampage

No.

or should I replace the FCU with a DP switch.

Depends on why there's an FCU in the first place.

I think both appliances will draw in the region of 2000w each

You shouldn't design stuff on the basis of "I think the load is....".

...alternatively, is there a switch that could replace the twin and FCU...something that I could neatly label and control the power to each appliance? all my other sockets are MK electrics.

Depends on why there's an FCU in the first place, but if it's just for that socket then depending on how it's connected to the socket circuit, and what type of socket circuit you have, then you could replace it with 2 FCUs supplying two sockets or two flex outlets, or an unswitched FCU and then two switches going to two sockets or two flex outlets.

But you will need to understand what you currently have, and why, and what the rules are for different arrangements, and of course changes like that are notifiable...

 

[oharaf]

BAS/ RF et al. correct me when I go wrong please!!!!


P= IV so assuming both are on at the same time

4000/ 230 = 17.4 A so this would suggest no you can't.

However, are you likely to be using both at the same time for prolonged periods?

however applying diversity

4000/230 = 17A so 10A + 30% of 7A + 5A for the socket

= 10 + 2 + 5 = 17A

So still a no!!

If only 1 appliance is to be used at a time

2000/230 = 8.7A so you would be fine.

I really haven't helped you here have I!!!!!

 

[captaincoxman]

crickey!...the FCU is isolating the twin...nothing else connected to it. It looks like the FCU is a spur of off the main ring. I've just noticed grid systems, so this could be a neat way to go...I could get a grid switch for each appliance (they look like they are pre labled aswell)...

 

[ban-all-sheds]

BAS/ RF et al. correct me when I go wrong please!!!!

OK

P= IV so assuming both are on at the same time

4000/ 230 = 17.4 A so this would suggest no you can't.

Look more closely at the time-current curves - a 13A fuse can withstand over 20A indefinitely.

However, are you likely to be using both at the same time for prolonged periods?

Tumble driers go flat out all the time, washing machines fluctuate. See the diagram here.

4000/230 = 17A so 10A + 30% of 7A + 5A for the socket

= 10 + 2 + 5 = 17A

So still a no!!

Thats the diversity calculation for a cooker circuit...

 

[ban-all-sheds]

crickey!...the FCU is isolating the twin...nothing else connected to it. It looks like the FCU is a spur of off the main ring.

Then you can't replace it with 2 FCUs or with two switches.

I've just noticed grid systems, so this could be a neat way to go...I could get a grid switch for each appliance (they look like they are pre labled aswell)...

You could, but you'd still need a 13A FCU before the grid, so your fuse concern remains unaddressed.

 

[captaincoxman]

im surprised this is turning out to be so difficult. All I want to do is keep the ability to isolate the power to the twin socket....the FCU does this and it looks like this set up was for a tumble beforehand (there is a vent in the wall). I want to use the same twin for the washing machine (this is why I was concerned about the 13a fuse)....could I not just replace the FCU with a higher amp switch? I've got an electrician coming out soon, so I will see what he says....

 

[pompeygit]

surely another point is that although you have a twin socket it shouldnt be loaded with more than 13 amps. Just cos its got 2 holes doesnt make it suitable for two heavy duty appliances or twice the load of a single socket

 

[GaryMo]

surely another point is that although you have a twin socket it shouldnt be loaded with more than 13 amps. Just cos its got 2 holes doesnt make it suitable for two heavy duty appliances or twice the load of a single socket

MK twin sockets are rated at 26A total, 13A for each outlet.
Why wouldn't they be?

 

[ban-all-sheds]

Because they don't have to be to meet the minimum laid down by BS1363?

 

[GaryMo]

So a case of when is a 13A socket not a 13A socket?

Is that true of all mainstream quality sockets?

The only one I've checked is MK and as I said, a twin socket is rated at 26A.

 

[ban-all-sheds]

Is that true of all mainstream quality sockets?

Dunno.

The only one I've checked is MK and as I said, a twin socket is rated at 26A.

Up to a few years ago they weren't, IIRC...