FCUs - Electricity needed for 2 Digital showers

[PaullyC]

i have recently had one bathroom redone. A spur was taken from a plug in the airing cupboard and put into a switched FCU with a 3 amp fuse as per Mira digital installation.

The second bathroom is now being done with another same digital shower next door to the other one.

I am assuming I cannot connect the two digital showers to this one 3 amp FCU?

Can I change the switched 3amp to an unswitched 13amp ?
Then connect two 3 amp switched fc units to the load side of the 13amp unswiched FCU.

My crude thinking is this then means each shower can have its 3amp fcu as per manufacturers instructions and the 13amp one will protect the cable and radial.

The consumer unit was also recently replaced with all seperate RCBOs

Is this allowed or any better suggestions please?

 

[telectrix]

NO.... what you do is to fit another 3A FCU. this can be fed from the incoming side of the existing 3A FCU, or from elsewhere on the circuit.

 

[westward10]

Yes if I read you correctly, one unswitched fcu with the two 3A fcus from its load side.

 

[PaullyC]

Thanks - I wanted to do that. I thought that would be viewed as 2 spurs off 1 spur. But if not that is great news.

 

[PaullyC]

Yes if I read you correctly, one unswitched fcu with the two 3A fcus from its load side.

Yes that was my initial idea.

In series or just both connected straight to load of unswitched FCU

Thanks for replying

 

[Wilko]

But why have two fuses in series? (as per Tel )

 

[telectrix]

as long as the 2nd FCU is fed from the incoming side of the first, it's just 2 x FCUs from the same point on the circuit If it were both FCUs were 13A, that could possibly cause an overload to the point on the circuit, but 2 x 3A is no problem. I assuming the circuit is a RFC, not a radial.

 

[PaullyC]

The initial feed to the current FCU is a spur cable from a mains socket ring.

 

[suffolkspark]

I guess adding another fused connection unit is really then a double spur off the ring, but as theyll both draw no more than 3A as said the risk of overload is non existant... Id be tempted to stick the second shower pump in the same fcu though tbh if it were my own house

Im sure your electrician will do it properly though and make sure its all safe and compliant... Let us know how he/she does it

 

[GeorgeCooke]

I am assuming I cannot connect the two digital showers to this one 3 amp FCU?

You almost certainly could, particularly as you are unlikely to use both showers at the same time.

Or put a 5 amp fuse in the FCU.

Remember manufacturers instructions are guidance only and don't have to be religiously followed.
Think what happens when those showers are used in the majority of countries where FCUs are unavailable and non compliant. They are put straight onto a 16 amp circuit. The showers should be internally protected.

 

[GeorgeCooke]

Yes that was my initial idea.

In series or just both connected straight to load of unswitched FCU

Thanks for replying

No such items should never be connected in series as you will get half voltage to each. They would be connected in parallel.

 

[Strima]

By rights you can’t have a spur from a spur but I don’t see a problem in this scenario as there’s no risk of overload during normal operation.

You could protect the whole spur by have a 13 amp unswitched FCU to protect the cable if you really wanted to abide by the regulations fully.

I would put the showers on double pole switched FCUs so you could isolate in case of fault in the future.

As these are supplying a special location you will more than likely need RCD protection and part P notification depending on your location.

 

[westward10]

He is protecting them both with one spur.

 

[Taylortwocities]

What is the actual power requirement of the Mira Digital Shower?

My guess is that it'll be <1amp, so you could have both showers on one 3amp FCU.