two 7.5kw showers!

[jacko57]

partitioning two large bedrooms to accomadate an en-suite in each,want to instal a 7.5kw shower in each
if thet are both running at the same time,and maybe the cooker /lights as well,this will be very close to the incoming fuse, 100amp single phase.
should i be thinking of an alternative in one of the en-suites?

 

[Steve]

yes. power shower - electricaly pumped mixer shower. Widely available, some look like normal electric showers. Only use about 100 watts, as opposed to 7500.

 

[ebee]

partitioning two large bedrooms to accomadate an en-suite in each,want to instal a 7.5kw shower in each
if thet are both running at the same time,and maybe the cooker /lights as well,this will be very close to the incoming fuse, 100amp single phase.
should i be thinking of an alternative in one of the en-suites?

unless you can wire in an interlock to prevent both being used at once

 

[Steve]

been thinking:

2 x 7.5kw showers = 62 amps.
cooker after diversity = approx 20amps
general lights = 5amps
rest of general evening appliances = 7amps

94 amps. as these showers are only 7.5kw (as opposed to 10.8kw ) i would say go for it. Your 100amp service fuse will not blow the instant you exceed 100 amps. It blows instantly at some insane current like 800amps. It can easily pass something like 110amps indefinitely.

Make sure your consumer unit is up to the job (newish model). If it is a Wylex rewireable board get it replaced. I think these were only designed for something like 60amps.

 

[Big_Spark]

Jacko...how is your hot water heated?

 

[Adam_151]

Yeah, I think you can do it if you have a 100A service fuse, and you stretch diversity on the rings a little, you should try not to go over the stated capacity of the service fuse, even though it'll hold for short duration overloads, once in a blue moon is one thing, if it happens often, then the service is being overloaded and its a dodgy thing to be doing

 

[Lectrician]

Alot of people run upto the capacity of the service fuse, although usually, the maximum demand agreed at connection is in the region of 12kw!

The lecky board and supplier don't seem to batter an eyelid when domestic customers pull more, but they hit commercial properies hard. They will fine you every month if you exceed the agreed maximum demand, as you pay an availability charge each month based on your maximum demand.

 

[plugwash]

i presume they can only do this if the installed meter can measure max demand.

 

[jacko57]

Cheers crafty,
property less than 8yrs old ,so all up to current regs.

if ok to install theses two seperate units,would i be best to go for two individual cable runs back to cu,then into 40amp shower rcds, or would i be able to run one 16/20 amp cable,and split the units into two?

 

[Adam_151]

Individual radial circuit for each shower, i'd use 10mm² cable, incase in future anyone wants to replace one of the units for a bigger one, and loose the other one, and also it gives you more room with regards to derating factors. (though don't run through thermal insulation with the cable).

Stick each one on a separate 40A breaker on the RCD side of the CU

What are your plans re: part p ?

 

[ban-all-sheds]

would i be able to run one 16/20 amp cable?

That wouldn't cope with the load of one shower, let alone two...