Shower Install

[m4tty]

Hi,

Scenario is: BS3036 Rewirable Fusebox. Customer wants new shower installed (Say 7.5kw/Clipped Direct/No Grouping/Insulation) . No shower at present. Is the best option to split the tails into Henley block then put a Shower CU with RCD (MCB 32a/6mm cable) next to 3036 Fuseboard then run cable to Isolator outside Bathroom then to Shower.

Is there any other ways of doing this??

Thanks

 

[Lurch]

Remember to also include the main isolator covering both CU's.

 

[Andy™]

split the tails. i never have one switch feeding both

 

[spinlondon]

I thought BS7671 required a single point of isolation?

 

[m4tty]

DNO Fuse ???

 

[bulmer]

I thought BS7671 required a single point of isolation?

For each installation. Each CU would be classed as a seperate installation and each CU has its own main point of isolation.

 

[Evans Electric]

Two choices I think Matty, change the board or split the tails. I see Lurchio raised the isolator question. For commercial and industrial premises , yes, that is :- there must be one main point of isolation but domestically it has been ignored by all and sundry for years . I don't actually know if it applies to domestic , lets see what the forum thinks.

 

[tom1]

is it possible to take an rcd in an enclosure from a rewirable fuse?

 

[ProDave]

is it possible to take an rcd in an enclosure from a rewirable fuse?

You can get 45A cartridge fuses for the old wylex boards (I have a couple) but personally I wouldn't do that, just split the tails and a separate shower CU.

 

[sellers]

Invent an RCBO version of these and you'll make millions.

 

[Andy™]

Invent an RCBO version of these and you'll make millions.

be aware that the holder the holder on the right (if there is one) is designed for 40/45A. all the others are designed for 30A

 

[Andy™]

Two choices I think Matty, change the board or split the tails. I see Lurchio raised the isolator question. For commercial and industrial premises , yes, that is :- there must be one main point of isolation but domestically it has been ignored by all and sundry for years . I don't actually know if it applies to domestic , lets see what the forum thinks.

depends on your version of the regs. ive always been told & believe its for each CU, not building.

id like to see you have one main switch in a large building that has more than one supply

the person doing the work should be competent enough to isolate safely and know there may be more than one 'main switch'

 

[sellers]

It must be for each CU. How can you technically work in the shower unit without isolation. I doubt DNO fuse is a practical way of isolation. Same applies for the DP isolator in a CU otherwise why would they make them with them?

 

[Lurch]

is it possible to take an rcd in an enclosure from a rewirable fuse?

You can but a lot of the old Wylex 3036 boards have 60A main switches and considering it's a few years old I'd just avoid touching it.

 

[SPECIAL LOCATION]

Two choices I think Matty, change the board or split the tails. I see Lurchio raised the isolator question. For commercial and industrial premises , yes, that is :- there must be one main point of isolation but domestically it has been ignored by all and sundry for years . I don't actually know if it applies to domestic , lets see what the forum thinks.

537.1.3

Each Installation shall have provision for disconnection from the supply!

537.1.4

A main linked switch or linked circuit breaker shall be provided as near as practicable to the origin of every installation as a means of switching the supply on load and as a means of isolation.

A main switch for use by ordinary persons, e.g. household or similar installations, shall interrupt Both live conductors of a single phase supply.

132.15.1

Effective means suitably placed for ready operation shall be provided so that all voltage may be cut off from every installation,

From every final circuit thereof

and from all equipment as may be necessary to prevent or remove danger

IN addition to the origin

537.2.1.1 then goes on to say that final circuit need there own isolation as well

and

537.2.1.2 also say equipment can need measure to prevent unintentional energising.

Other good reading

page 33 OSG

5.1 isolation

5.1.1 requirement

i At the origin of the installation.

Its make your minds up time folks.....................?

 

[SPECIAL LOCATION]

You can but a lot of the old Wylex 3036 boards have 60A main switches and considering it's a few years old I'd just avoid touching it.

Concur with Da Lurch!!!!

on that one!

:xApplaud SmileyApplaud SmileyB-)

 

[Andy™]

537.1.3Each Installation shall have provision for disconnection from the supply!

537.1.4

A main linked switch or linked circuit breaker shall be provided as near as practicable to the origin of every installation as a means of switching the supply on load and as a means of isolation.

A main switch for use by ordinary persons, e.g. household or similar installations, shall interrupt Both live conductors of a single phase supply.

132.15.1

Effective means suitably placed for ready operation shall be provided so that all voltage may be cut off from every installation,

From every final circuit thereof

and from all equipment as may be necessary to prevent or remove danger

IN addition to the origin

537.2.1.1 then goes on to say that final circuit need there own isolation as well

and

537.2.1.2 also say equipment can need measure to prevent unintentional energising.

Other good reading

page 33 OSG

5.1 isolation

5.1.1 requirement

i At the origin of the installation.

Its make your minds up time folks.....................?

Part 2 definitions

Electrical Installation: 'An assembly of associated electrical equipment having co-ordinated characteristics to fulfil specific purposes'

Origin of installation: 'The position at which electrical energy is delivered to an electrical installation'

so if each DB is its own installation, then the origin of each installtion will be the tails feeding it. so providing each DB has its own main switch, then all regs are met, and you dont need an isolator on tails

 

[Lurch]

[quote name='Andy

 

[Andy™]

Depends which way you read it, as with just about every regulation. 2 DB's supplied and fitted with 1 specific purpose of providing power and lighting to a house counts as one, if you read it that way, which is the way I do.

like you say, depends on how you read it.

still using your same situation of power and lighting, one installation could be specifically for lighting form from DB1, and another installation specifically for sockets fed from DB2, so you have 2 installations, and therefore one main switch for each, but not a common switch

 

[kme]

Nah, I`m on a "common" switch theory - having just re-read definitions of "installation"; AFAIAC you do NOT need seperate isolators; although the main switches of the units will provide this. One main switch, feeding to several sub-boards wouldn`t IMO, need isolation, other than the main switch within the CU/DB.

However, I do agree that it is always better to have seperate, individual means of isolation, as far as practicable. But, regs wise, I don`t believe an "installation" is taken from the DBs/CUs, I take it as the supply to a premises from one metering position / service head.

KME