Electric Shower on a 63A Main switch CU

[ianphilip007]

hi guys

after a little advice,

customer wants an 8.5kw shower fitted to a C.U with a 63a Main Switch. i assume main fuse is 60A. existing circuits Cooker radial 30a mcb, 1 ring main 30a mcb, 1 radial lighting circuit 5 mcb( its a bungalowe )

with diversity applied (quick calculation) 30+5+30+40 x 0.4 = 30
so appears fine but was just reading some literature from Gainsbourgh showers stting that the cu shouls have a minimum rating of 80 amps.

any thoughts

 

[ianphilip007]

to add

using common sense max demand would never be exceeded with normal everyday use. just made me think when i saw the installation instructions from gainsbourough.

 

[davelerave]

our standard domestic is 63amp here(roi)

there's usually no problem with instantaneous shower+elec. cooker and sockets

 

[telectrix]

swap the main switch for a 80A. you are then following manufacturers instructions. if the DNO fuse is sufficiently overloaded to blow (which i doubt) DNO can uprate to 80A or 100A.

 

[malcolmsanford]

Is this CU an old BS 3036 rewirable type as that switch sounds like an old BS 5419 type.

If the manufacturers instructions tell you the board must conform to BS EN 60439-3, then I would think about fitting a small shower enclosure seperate from the existing CU.

 

[MarkieSparkie]

There is no diversity applicable to the first instantaneous water heater (shower), so you will need to uprate the CU main switch if you intend to run the final circuit from there. The shower is a special location so you will need 30mA RCD protection, so a separate shower RCD/MCB CU might be a better solution. However your customer may wish to take this opportunity to have a full 17th ED board change upgrade.

 

[Octopus]

Henley block and shower CU would be my suggestion, plus the obligatory look/upgrade of the bonding too!

 

[ianphilip007]

is it nessacary to split the tails or can i feed a seperate shower cu from the existing spare way in the board

 

[Deleted member 26818]

is it nessacary to split the tails or can i feed a seperate shower cu from the existing spare way in the board

Is this a trick question?

 

[1shortcircuit]

Henley block and shower CU would be my suggestion, plus the obligatory look/upgrade of the bonding too!

is it nessacary to split the tails or can i feed a seperate shower cu from the existing spare way in the board

Is this a trick question?

The reason for splitting the tails into Henley blocks is to allow you to fit a separate CU and not interfere with the other consumer and the concern of the main switch

Please be sure to follow the safe isolation procedure in full :thumbsup

 

[Octopus]

The reason for splitting the tails into Henley blocks is to allow you to fit a separate CU and not interfere with the other consumer and the concern of the main switch

Please be sure to follow the safe isolation procedure in full :thumbsup

Also it means that the new circuit is protected by a RCD too!

 

[1shortcircuit]

Also it means that the new circuit is protected by a RCD too!

There is the blatantly obvious also lol