Power Shower wiring regulations

[cromwell66]

I have a Mira Essentials power shower. It was installed by the previous occupant who happens to be a plumber.

I like to confirm that it is wired in correctly as I keep getting different opinions on how it should be connected.

It is currently thruwall connected to a 3 AMP RCD plugged into a socket in the airing cupboard.

Recently a plumber told me this is incorrect as it should be connected as per the regulations for an "instant electric" shower, ie wire as per rating, independant spur, pull cord, etc, etc.

Yet my Readers digest DIY book suggests that this not required, as do other internet sites.

Can anyone point me to correct regulations for wiring a power shower that does not heat its own water and uses domestic hot and cold water off our own tanks?

TVM

Cromwell

 

[Slugbabydotcom]

I've edited a bit out here cos I never read the post properly first time round

Installation instructions usually provide sufficient advice.

The following is typical however it is not for the one you have.

The shower must be connected to a 230/240 volt. A.C electrical supply from a
13-amp ring main, via a fused double pole switch with at least 3mm contact
separation. The switch is to be clearly identifiable, but out of reach of a person using
a fixed tap or shower, i.e. mounted in an adjacent room. It should be fused at
no more than 3 amps

 

[cromwell66]

Obviously it's not instant...but do the same wiring regs apply as suggested?

No Installation book as it was already installed.

 

[Slugbabydotcom]

Post edited above
Contact Mira for their version but all sounds well to me

 

[chrishutt]

I have a Mira Essentials power shower

No such thing on the Mira site. Are you sure you've got the name right? It's not the Event, is it.

 

[Softus]

It is currently thruwall connected to a 3 AMP RCD plugged into a socket in the airing cupboard.

This is undesirable on several counts:

1. You should avoid power sockets in an airing cupboard because of the higher temperature; however 3A is not a lot.
2. A power socket does not incorporate a double-pole switch.

Recently a plumber told me this is incorrect as it should be connected as per the regulations for an "instant electric" shower, ie wire as per rating, independant spur, pull cord, etc, etc.

Ask an electrician, not a plumber. A pull cord is not compulsory.

Can anyone point me to correct regulations for wiring a power shower that does not heat its own water and uses domestic hot and cold water off our own tanks?

I don't understand - do you mean a self-contained shower valve/pump, rather than a remote pump?

 

[cromwell66]

Firstly......many thanks to Slugbabydotcom Softus and chrishutt for replies so far.

It is an "Essentials" shower...I believe the range is not current any more.

I don't understand - do you mean a self-contained shower valve/pump, rather than a remote pump?

yes it is self contained...sri about confusion. When I explain to others what type of shower it is, it is often confused with an instant electric shower, hence I tried to be "over-exact"!.

1. You should avoid power sockets in an airing cupboard because of the higher temperature; however 3A is not a lot.
2. A power socket does not incorporate a double-pole switch.

1. does the higher temperature degrade the performance of the RCD?

2. I assume a double switch could be easily fitted in lieu of a socket, but what difference does it make if always left on as is typical in most fittings?

Again many thanks for all the replies

Cromwell

 

[Softus]

1. does the higher temperature degrade the performance of the RCD?

I would expect not, but this is a non-authoritative answer. The more important point is that it's the wrong type of protection.

2. I assume a double switch could be easily fitted in lieu of a socket, but what difference does it make if always left on as is typical in most fittings?

That's a bit like asking the point of having a switch at all! The point is, when you need to isolate the shower it should be via a double-pole switch. Clearly, if you unplug it then it's even better, but if the power socket has a switch (which some do) then it's possible to make a potentially fatal mistake.

 

[Slugbabydotcom]

A power socket does not incorporate a double-pole switch.

A power socket is the best TRIPLE pole switch you are ever going to get if you unplug it!!

 

[Softus]

A power socket is the best TRIPLE pole switch you are ever going to get if you unplug it!!

Either that's irrelevant, or we should be fitting sockets and plugs instead of FCUs.

 

[oldrocker]

I know it's a bit late but for any future reference this extract is taken from a current Mira Power Shower installation guide.

"2.2. The mains supply must be 230-240 V at 50 Hz connected to the appliance via
a double pole switched 3 Amp fused connection unit (not supplied) with a
minimum 3 mm contact separation gap in each pole.
2.3. Fuses do not give personal protection against electric shock.
2.4. The Mira Event XS must be earthed by connecting the supply-cable earth
conductor to the earth terminal.
Supplementary bonding: Within the bathroom or shower room, all accessible
conductive parts of electrical equipment and extraneous conductive parts that
are likely to introduce earth potential, must be electrically bonded to earth
using a minimum cable size of 4.0 mm2 if the cable is not mechanically
protected (2.5 mm2 if mechanically protected).
11
2.5 The minimum cable size (cross-sectional area) required is 1mm2 under normal
conditions of installation.
2.6. A 30mA residual current device (RCD) must be fitted. This may be part of the
consumer unit or a separate unit."