What kind of Electric Shower install is possible with my existing consumer unit?

[fearny26]

Hi I am moving into a ground floor flat and would like to have a new electric shower installed above an existing bath tub, unfortunately due to low pressure from the hot water tank a plumber has advised a mixer shower is not an option and neither is a pump. I am rather new to all this sort of thing so apologies if anything I explain does not make sense.

The install itself seems pretty straightforward. Shower on the wall above the tub, isolator pull cord from the ceiling and then approx 10-15m cabling and trunking to the consumer unit which is in an enclosure on the wall of my bedroom.

Here's where I am unsure of the best way to proceed. The flat is setup for economy 7 tariff and as such the meter tails are split in a henley block and feed two Wylex fuse boxes, one rated to 100a and one to 60a. Both fuse boxes are also connected to an RCD rated 80a and 30ma tripping current. Both fuseboxes have a spare way each. The service fuse states 100a. The flat is all electric and has a cooker, an immersion heater, one storage heater.

As a side note once the shower has been installed it will make the boiler redundant and will likely never be used. I'm unsure if that will affect the shower install but just thought I'd mention. This will also mean the only appliance that can take advantage of the economy 7 tariff I'm currently on is the one storage heater and so I would be interested in changing the setup to support a normal tariff but I am unsure of the work needed to do that and any advice is appreciated. Finally I am renting this flat with one other person and its most likely it will just be for 1 or 2 years so while we would like to spend money on the shower and are happy to spend a little bit more if it means getting a more powerful shower. We would not be interested in any major work such as changing to a new CU as the cost will more than likely outweigh the benefit to ourselves in the short term and we are also living on a budget.

So I would like to know if its possible to wire up a shower straight into my existing setup and if so whats the highest strength of shower it can support?

Is it possible to wire up a separate shower consumer unit and would this allow for a higher rated shower?

If I wanted to change my tariff from economy 7 is it a big job or straightforward?

I have had one spark round so far but he seemed rather put off by my fusebox and I got the feeling he didn't want to know. He quoted £400 and said he could install an 8.5kw shower but anything higher and he said he would need to replace the entire CU and would be in excess of £1000.

Thanks so much
Jake

 

[telectrix]

a 8.5 kW shower wolud not be a problem connecting to that CU, maybe even a 9.5kW. altogh that CU is not ideal, there is a 30mA RCD protecting the installation, so it would be do-able without a great cost.

 

[Gary Gemmell]

Hi I am moving into a ground floor flat and would like to have a new electric shower installed above an existing bath tub, unfortunately due to low pressure from the hot water tank a plumber has advised a mixer shower is not an option and neither is a pump. I am rather new to all this sort of thing so apologies if anything I explain does not make sense.

The install itself seems pretty straightforward. Shower on the wall above the tub, isolator pull cord from the ceiling and then approx 10-15m cabling and trunking to the consumer unit which is in an enclosure on the wall of my bedroom.

Here's where I am unsure of the best way to proceed. The flat is setup for economy 7 tariff and as such the meter tails are split in a henley block and feed two Wylex fuse boxes, one rated to 100a and one to 60a. Both fuse boxes are also connected to an RCD rated 80a and 30ma tripping current. Both fuseboxes have a spare way each. The service fuse states 100a. The flat is all electric and has a cooker, an immersion heater, one storage heater.

As a side note once the shower has been installed it will make the boiler redundant and will likely never be used. I'm unsure if that will affect the shower install but just thought I'd mention. This will also mean the only appliance that can take advantage of the economy 7 tariff I'm currently on is the one storage heater and so I would be interested in changing the setup to support a normal tariff but I am unsure of the work needed to do that and any advice is appreciated. Finally I am renting this flat with one other person and its most likely it will just be for 1 or 2 years so while we would like to spend money on the shower and are happy to spend a little bit more if it means getting a more powerful shower. We would not be interested in any major work such as changing to a new CU as the cost will more than likely outweigh the benefit to ourselves in the short term and we are also living on a budget.

So I would like to know if its possible to wire up a shower straight into my existing setup and if so whats the highest strength of shower it can support?

Is it possible to wire up a separate shower consumer unit and would this allow for a higher rated shower?

If I wanted to change my tariff from economy 7 is it a big job or straightforward?

I have had one spark round so far but he seemed rather put off by my fusebox and I got the feeling he didn't want to know. He quoted £400 and said he could install an 8.5kw shower but anything higher and he said he would need to replace the entire CU and would be in excess of £1000.

Thanks so much
Jake

Forgive me if i am wrong but your E7 meter should supply all your leccie at night on rate 2 including the lights, ring main, shower, water heater etc!

Why would your boiler be of no use - dont you use hot water in the taps in bathroom and kitchen?

I am having my comfortplus white meter Horstmann replaced with an E7 for just this reason!

 

[ferg]

It really depends on how low your water pressure is.

If it's too low then some modern electric showers will stop heating when on a higher temperature setting.

 

[davesparks]

Hi I am moving into a ground floor flat and would like to have a new electric shower installed above an existing bath tub, unfortunately due to low pressure from the hot water tank a plumber has advised a mixer shower is not an option and neither is a pump. I am rather new to all this sort of thing so apologies if anything I explain does not make sense.

Considering that the whole point of a pump is to fix low pressure I would say the plumber is talking nonsense.
Talk to a couple of other reputable plumbers to get other opinions.
Personally I would avoid having an electric shower if at all possible, they are a poor, ugly, expensive substitute for a proper shower.
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It might be worth looking at this new product @Dan has posted about

Shower Power Booster - Had a drop in water pressure?

https://www.plumbersforums.net/threads/shower-power-booster-giveaway-competition-ends-31st-december.111068/ There's a deal on these, but even when there isn't a deal going they can be a godsend. These little gizmos fire up the pressure of the water feeding your shower (or other taps)...

www.electriciansforums.net

Source URL: Shower Power Booster - Had a drop in water pressure? - https://www.electriciansforums.net/threads/shower-power-booster-had-a-drop-in-water-pressure.181422/#post-1594947

 

[Gary Gemmell]

Considering that the whole point of a pump is to fix low pressure I would say the plumber is talking nonsense.
Talk to a couple of other reputable plumbers to get other opinions.
Personally I would avoid having an electric shower if at all possible, they are a poor, ugly, expensive substitute for a proper shower.

Why not plumb it into the mains supply thats what i did with ours!
Only problem will be getting to the pipes if its under a tiled floor - nightmare then!

Much better pressure but still not as good as my local gym sadly!
Nice to have a power shower but each electrical item you add like a pump is just another point of failure and expensive layout in terms or reapirs and extra leccie!

 

[fearny26]

Sorry there is some confusion guys I will clear this up.

The water pressure for the cold mains is brilliant and it is this that I will use for the electric shower. The hot water pressure is poor due to the boiler/tank being at the same height as the shower and only a few meters away from the bathroom and this is the reason the plumber recommended an electric shower. I was not there when he said why he could not use a pump on the hot water tank feed but I believe it is due to the boiler being ground floor and the lack of space to install.

As for not using the boiler once the shower is in place its because its a large cupboard size tank and it would not be economical to heat the entire tank to just use a small amount of hot water for washing up each day. There are only 2 of us living here and we would not be taking baths.

I believe it would make sense to change from economy 7 as it would really only be the one storage heater on during off peak hours once the shower is in place as the boiler would probably never be used and theres not anything else I would be doing during those hours.

Thanks for you replies already
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a 8.5 kW shower wolud not be a problem connecting to that CU, maybe even a 9.5kW. altogh that CU is not ideal, there is a 30mA RCD protecting the installation, so it would be do-able without a great cost.

Would you just use the spare way on the fuseboard to do this and are you able to give a ball park figure for the work?

Thanks
Jake

 

[Gary Gemmell]

Sorry there is some confusion guys I will clear this up.

The water pressure for the cold mains is brilliant and it is this that I will use for the electric shower. The hot water pressure is poor due to the boiler/tank being at the same height as the shower and only a few meters away from the bathroom and this is the reason the plumber recommended an electric shower. I was not there when he said why he could not use a pump on the hot water tank feed but I believe it is due to the boiler being ground floor and the lack of space to install.

As for not using the boiler once the shower is in place its because its a large cupboard size tank and it would not be economical to heat the entire tank to just use a small amount of hot water for washing up each day. There are only 2 of us living here and we would not be taking baths.

I believe it would make sense to change from economy 7 as it would really only be the one storage heater on during off peak hours once the shower is in place as the boiler would probably never be used and theres not anything else I would be doing during those hours.

Thanks for you replies already
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Would you just use the spare way on the fuseboard to do this and are you able to give a ball park figure for the work?

Thanks
Jake

I think i see what you mean it just came across as you were using the hot water feed into the electric shower which is a bit mad as it should be a cold feed!

I presume you have a combi boiler I keep relating it to my setup which is a vented cylinder type boiler which i prefer to a combi anyway as like you I never use hot water except for having a bath so can dig where you are coming from viz a viz saving the cash on heating the water - it is a bit much just to do the dishes and splunge yer face for having a shave lol.

I wired my boiler up using a sonoff 15 amp smart switch which means i can switch it on when i am on the bus on the way home so its piping hot when i get in and i can see all the stats on power used cost etc on the inteface to the sonoff so you might consider that if you want to save cash - you can also set it on a timing basis to go on and off at set times but to be able to do it from your smartphone is just the dogs!

 

[Vortigern]

I would get a price on a new combi boiler to run your shower off of and a price for fitting an electric shower you might find it is far more economical in the long run to run off a combi and modernise your flat and get rid of the boiler tank and get more storage room. Just a thought.

 

[fearny26]

I would get a price on a new combi boiler to run your shower off of and a price for fitting an electric shower you might find it is far more economical in the long run to run off a combi and modernise your flat and get rid of the boiler tank and get more storage room. Just a thought.

Yes certainly in the future a small water heater would be ideal.

To Gary, it's actually an electric immersion heater on the water tank so yeah like you said a bit much just for a small amount of hot water use outside of showers. I'm not in a position to change anything big time right now so I'm happy to just heat up the kettle for washing up etc. Right now I'm purely focused on getting the shower in at a reasonable cost but all nice ideas for the future.

 

[freddo]

Would you just use the spare way on the fuseboard to do this

Thanks
Jake

The spare way will be rated 30A max. If you want more than a 7.2KW shower you will need to check that the fuseway next to the main switch is rated for up to 45A use and move the circuit that is currently there. Or if it isn't, then you will need to install a separate switchfuse for the shower.

I would get a price on a new combi boiler to run your shower off of and a price for fitting an electric shower you might find it is far more economical in the long run to run off a combi and modernise your flat and get rid of the boiler tank and get more storage room. Just a thought.

If you have the money this is an excellent way to go.

 

[Vortigern]

ball park figure

£700-£1000 which is why I said compare the price for a combi

 

[littlespark]

Theres no problem adding an electric shower to your setup... but I would go for a separate board and RCD just for the shower. If it trips, it doesn't take out your entire house.

I would agree that the boards need upgraded, £1000 seems a bit steep, but I don't know what horrors are lurking behind the covers.

You are renting? Dont want to alarm you, have you seen an EICR (condition report) for the installation? Tenants don't normally, but you could say to your landlord that you're not happy with the old fuses and would like to see proof its all safe.

 

[Vortigern]

£1000 seems a bit steep

Just ball park. Looking at the RCCB I wonder if it might present problems and other thoughts hence a potentially higher price than normal as a guess. But I suppose as said by @littlespark separate RCD supply would make it cheaper as you can then just bypass the state of the existing wiring and hope it is ok for the client. Such a setup may well be ok, but then again a few tests might show up problems hence the reserve type price for those kind of problems.

 

[MJPD29]

Prices sound about right and his advice isnt far off either.

 

[Taylortwocities]

Forgive me if i am wrong but your E7 meter should supply all your leccie at night on rate 2 including the lights, ring main, shower, water heater etc!

you are wrong in this case.
there are two ways That E7 can be presented:
1. As you describe, everything comes off the same feed, but lower tariff at night time. Off peak devices like storage rads need separate timers.
2. as in this installation- there are two fuse boards. The off peak one only is energised at night time. Separate circuits run to storage rads, off-peak immersions, etc.
The 24-hour fuseboard does not benefit from a lower tariff at night.

 

[Zerax]

My two-penneth on this one is;

1. Ditch the E7 asap ! I have yet to find a situtation and tariff combination that makes any economic sense...
2. Have you considered an unvented direct cyclinder ? So you'll heat your water by immersion heater and get mains pressure for showers/washing up/wash basin. (Cylinder and kit is about £250 but you'll need pressure relief outlet and has to be installed by G3 plumber)
3. If you're set on an electric shower (I've tried a few over the years, and they're all awful) I'd say get the 9.5kW one... a smaller one in the summer would suffice when the cold water is not as icey cold as it is in the winter, when you're really notice the difference in flow.

 

[fearny26]

Hi guys thank you very much for all your replies

So am I right in saying that regarding installing the shower there are two possibilities?

One is to use the spare way on my existing fuseboard rated at 30a and I can have a 7.5kwh shower.

And the other is to install a separate shower consumer unit like this via a henley block

https://www.NoLinkingToThis/p/wylex-4-module-1-way-populated-shower-consumer-unit/3458j

and wire the shower from there.
I assume this means I can have a much more powerful shower even a 10.5kwh?
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My two-penneth on this one is;

1. Ditch the E7 asap ! I have yet to find a situtation and tariff combination that makes any economic sense...
2. Have you considered an unvented direct cyclinder ? So you'll heat your water by immersion heater and get mains pressure for showers/washing up/wash basin. (Cylinder and kit is about £250 but you'll need pressure relief outlet and has to be installed by G3 plumber)
3. If you're set on an electric shower (I've tried a few over the years, and they're all awful) I'd say get the 9.5kW one... a smaller one in the summer would suffice when the cold water is not as icey cold as it is in the winter, when you're really notice the difference in flow.

I'm really on a bit of a budget atm so having the boiler ripped out and replaced is not an option for me right now but I will note this down for the future. For sure I have read the same as what you say about the showers so I'm keen to get a good one in if my setup supports it.

Can I ask you though about my economy 7 setup again please. Would I be right in saying that if I have my energy provider change my tariff and meter would both my fuseboards then just go live 24/7? As I assume right now its setup so that one of the boards only goes live during the off peak hours. I'm just hoping its possible to change from E7 without having to replace my entire consumer unit.

(My meter is a digital one at the moment that provides both the on and off peak rates however I am in the process of having a smart meter installed)

Thanks
Jake