Shower isolation outside bathroom

[markthespark]

Hello just been to look at a shower install the consumer unit backs on to the wall that the shower is going on so the easiest option would be to fit an isolator below the consumer unit and drill straight through the wall.

Would this be ok to do or will i have to put the isolator outside the bathroom door?

For information its a single story flat no access above or below.
cheers.

 

[davesparks]

Electric shower or power shower?

Traditionally the isolator for an electric shower will be installed inside the shower room (45A DP pull switch)

 

[Meggerman]

Hello just been to look at a shower install the consumer unit backs on to the wall that the shower is going on so the easiest option would be to fit an isolator below the consumer unit and drill straight through the wall.

Would this be ok to do or will i have to put the isolator outside the bathroom door?

For information its a single story flat no access above or below.
cheers.

Yeah, definatly. What a nice easy job that one is eh. Has it got a spare RCD protected B40 MCB in DB aswell just to make it the perfect job . Good point Dave... Electric or power shower?

 

[davesparks]

I would say this is not really acceptable personally, and I certainly wouldn't do it that way.

I was taught that in domestic installations isolators should be installed adjacent to and in the same room as the equipment they isolate. And that a special case is made for bathrooms where the isolator a get installed adjacent to the door into the room.

 

[markthespark]

Sorry its an electric shower, 10.5KW running a 10mm cable in for it, no RCD in the board so going to henley block the tails into an rcd shower unit then out the bottom of that into a 45amp DP isolator just was unsure as its not inside the bathroom or directly outside.

the door for the bathroom is around the corner from the consumer unit about 3 metres away.

thanks

 

[davesparks]

10.5 KW at what voltage? All of the showers I've fitted have been rated at 240V with a lower 230V power rating.

 

[markthespark]

To be honest ive not even seen the shower, its a tenanted flat and the landlord say they have got a 10.5kw shower.

if the isolator cant be fittes below the CU then ill have to run trunking around the top of the wall and drop down outside the bathroom door which id rather not do.

thanks

 

[combilau]

Yep that's fine as long as the customer knows where is it or it's labeled should be fine, Dave all electrical calculations are worked out on 230v not 240v

 

[markthespark]

Thanks very much

 

[davesparks]

Yep that's fine as long as the customer knows where is it or it's labeled should be fine, Dave all electrical calculations are worked out on 230v not 240v

No they aren't! Calculations are worked out on the voltage of whatever system you are working with! That's why all of the equations use V not just the number 230!

Most showers still have their power ratings quoted at 240V with their 230V rating appended to it.

 

[combilau]

No they aren't! Calculations are worked out on the voltage of whatever system you are working with! That's why all of the equations use V not just the number 230!

Most showers still have their power ratings quoted at 240V with their 230V rating appended to it.

Page 294 regs book I'm sure there's others too, they are worked out by nominal voltage not v!

 

[HandySparks]

If your new one way RCD DB is nice and accessible and reasonably close to the door of he bathroom, I don't see any need for additional isolation. Just make sure that it's properly labelled.

 

[GLENNSPARK]

Electric shower or power shower?

Traditionally the isolator for an electric shower will be installed inside the shower room (45A DP pull switch)

what a load of old crap.

to the OP:

perfectly acceptable to site the DP iso where you intend.

 

[davesparks]

I really do despair for the state of this once noble trade!

Forget the regs book we are dealing with basic physics! V=I.R P=I.V not 230=I.R or P=Ix230

Installation calculations are carried out using nominal voltage in the absence of any more accurate information.

Power ratings are quoted at a specific voltage, to then use a different voltage in calculations involving that power rating is wrong as the power will be different at a different voltage.

Electric showers are almost universally rated at 240V so you need to use 240V in any calculation relating to their power rating.
So for a 10.5KW shower at 240V we get a current flow of 43.75A
If we did as you suggest and used 230 instead then we would wrongly calculate the current as being 45.7A

To establish the actual current flow at 230V we would need to first work out the impedance of the load (R in the above formulas) then we could work out the power and current at 230V

 

[GLENNSPARK]

I really do despair for the state of this once noble trade!

Forget the regs book we are dealing with basic physics! V=I.R P=I.V not 230=I.R or P=Ix230

Installation calculations are carried out using nominal voltage in the absence of any more accurate information.

Power ratings are quoted at a specific voltage, to then use a different voltage in calculations involving that power rating is wrong as the power will be different at a different voltage.

Electric showers are almost universally rated at 240V so you need to use 240V in any calculation relating to their power rating.
So for a 10.5KW shower at 240V we get a current flow of 43.75A
If we did as you suggest and used 230 instead then we would wrongly calculate the current as being 45.7A

To establish the actual current flow at 230V we would need to first work out the impedance of the load (R in the above formulas) then we could work out the power and current at 230V

design....

 

[davesparks]

what a load of old crap.

to the OP:

perfectly acceptable to site the DP iso where you intend.

Please enlighten me as to why this insult is necessary? My statement that a 45A DP pullcord is the traditional method for providing an isolator for them is borne out by the vast majority of electric showers being installed in this way.

 

[davesparks]

design....

Good point, compromise at 'installation design'?

 

[GLENNSPARK]

Please enlighten me as to why this insult is necessary? My statement that a 45A DP pullcord is the traditional method for providing an isolator for them is borne out by the vast majority of electric showers being installed in this way.

rubbish.

a 45A DP iso...is just that...is it not?

and whether its sited within the location./...or not is neither here nor there....is it not.

 

[combilau]

I really do despair for the state of this once noble trade!

Forget the regs book we are dealing with basic physics! V=I.R P=I.V not 230=I.R or P=Ix230

Installation calculations are carried out using nominal voltage in the absence of any more accurate information.

Power ratings are quoted at a specific voltage, to then use a different voltage in calculations involving that power rating is wrong as the power will be different at a different voltage.

Electric showers are almost universally rated at 240V so you need to use 240V in any calculation relating to their power rating.
So for a 10.5KW shower at 240V we get a current flow of 43.75A
If we did as you suggest and used 230 instead then we would wrongly calculate the current as being 45.7A

To establish the actual current flow at 230V we would need to first work out the impedance of the load (R in the above formulas) then we could work out the power and current at 230V

All of our work is carried out to bs7671 and the calculations in there state 230v is used. It will state in the mi's a 230v rating and 240v rating in kW for the showers.

 

[GLENNSPARK]

All of our work is carried out to bs7671 and the calculations in there state 230v is used. It will state in the mi's a 230v rating and 240v rating in kW for the showers.

i`tl be nearer the 240V mark...i can tell you now...

and may be up towards 245-248.....

use nominals for design....but if installing go for measured....