I would be grateful for some advice regarding a potential electrical upgrade which I intend to get completed this summer when we have our kitchen and bathroom refurbished. I will engage the services of an electrician nearer the time, but wanted to explore some possibilities to help with planning the works.
A bit of context first - The property is a small ex-council 3 bed semi built in 1937 and most electrics appear to be from the 80s.
Everything is set up around economy 7 (no option for gas). Heating is delivered via 7 storage heaters, hot water comes from a cylinder with immersion element and the kitchen has a free standing electric cooker.
EON upgraded us to a smart meter when we moved in and fitted a separate non-adjustable time switch which activates the storage heaters via their own consumer units (2 in total).
The economy 7 night rate is active for 7 hours between 1:30 and 8:30 am in the summer, and 12:30 and 7:30 am in the winter.
The storage heaters collectively draw as much as 13.6 kw at peak. The 3 kw immersion is on a timer and generally used between 5:30 and 7.30 am, then a short boost 5:00 to 6:00 pm.
We don’t have a shower and would really like to fit a 10.5 kw unit when we upgrade the bathroom. This is where I have concerns – although our supply is rated at 100 amp, would I be in an overload situation if I was to shower when the storage heaters and immersion are all going together?
This is likely as we are all up and getting ready before the storage heaters switch off. Worst case scenario would be the storage heaters, immersion, hob plate and kettle are all going while the shower is active (other than these items we have very few other power demands).
I understand that principles of diversity may apply. In practice, when the storage heater circuits are first activated there is likely to be a big draw, but as we’re all in bed, by the time morning comes and we want to use the shower etc. most heaters will be up to temperature and only drawing intermittent power through thermostatic control. Of course, none of this is an issue in summer.
Should I instead consider a less power hungry 8.5 kw shower or do away with the idea and opt for better stored water and a pump (not preferred)?
Our current collection of consumer units (4) is a total mess so I will be getting quotes to have the lot upgraded. I am hoping it will be no more than 2 units, one for storage heaters the other for everything else.
I wanted to consider RCBOs instead of a dual RCD setup, but the cost may be prohibitive. I have thought about only applying the RCBOs to the main board, leaving the storage heaters protected by a single RCD. I have often seen showers on their own consumer unit but assume this wouldn’t be necessary with an appropriately sized consumer unit.
The electrician will need to install it all to meet regulation, so I may have no say in the matter on this point anyway.
Any advice or recommendations will be gladly received.
Daniel.
