Main fuse upgrade and associated issues

[Callcom]

I'm due to qualify as a domestic installer soon, and my brother, who is fully qualified, will be doing most of this work.

I have a 60A main fuse.
I currently have a typical domestic installation, i.e. cooker, immersion etc, and one electric shower.
Due to distances between hot/cold supply and downstairs bathroom, I want to fit an electric shower there too.
I'm also planning a new en-suite and want an electric shower there as well
i.e. 3 electric showers in total.

I can upgrade to 80A main fuse for free. 100A would cost nearly a grand.

Question: can I run 3 electric showers with an 80A main supply?

 

[Marvo]

Your brother would be the best person to ask as I assume he's familiar with your installation. Without a heck of a lot more details I can't answer any of your question. Ask him about applying diversity as well, what's the chances three showers will ever be running simultaneously in a normal domestic house?

 

[Engineer54]

3 electric showers in what, a typically sized 3 bed house (probably with gas central heating/hot water) .... Ridiculous is a word that quickly springs to mind!! lol!!

 

[Callcom]

3 electric showers in what, a typically sized 3 bed house (probably with gas central heating/hot water) .... Ridiculous is a word that quickly springs to mind!! lol!!

It's a 5-bed detached with no mains gas. The issue is that you need effectively a dedicated hot/cold supply for a pumped shower and the amount of work involved in plumbing that in is prohibitive.

 

[Guest55]

im already feeling sorry for the new to the forum OP after........

domestic installer

you can fit 20 showers so long as not more than 1at a time is switched on.
other than that run them off a combi boiler for considerably better performance.

 

[Callcom]

im already feeling sorry for the new to the forum OP after........



you can fit 20 showers so long as not more than 1at a time is switched on.
other than that run them off a combi boiler for considerably better performance.

Thanks for your answer. Yes, take that point, also diversity. What I'm trying to get are opinions as to what most electricians would advise their customer in this situation. Given that for most of the year it's unlikely that more than two showers would be on simultaneously, but that occasionally, with a house full of guests all three showers might be on, as well as the cooker.

We already have a large, oil-fired boiler, and the cost of a new one installed exceeds £2k. Also a combi would not be advisable given the size of house and water usage.

 

[Octopus]

Why ask here IF your brother IS real?

 

[GLENNSPARK]

and what business have you altering the I N of the DNO bullit?

chances are its a shared supply as well....

 

[Guest111]

and what business have you altering the I N of the DNO bullit?

chances are its a shared supply as well....

Maybe that's why he needs 3 showers,shared with the neighbours.lol

 

[MDJ]

I'm due to qualify as a domestic installer soon, and my brother, who is fully qualified, will be doing most of this work.

I have a 60A main fuse.
I currently have a typical domestic installation, i.e. cooker, immersion etc, and one electric shower.
Due to distances between hot/cold supply and downstairs bathroom, I want to fit an electric shower there too.
I'm also planning a new en-suite and want an electric shower there as well
i.e. 3 electric showers in total.

I can upgrade to 80A main fuse for free. 100A would cost nearly a grand.

Question: can I run 3 electric showers with an 80A main supply?

Congratulations, you should know the answer to your own question then. Out of interest what does your Brother think?

 

[Callcom]

im already feeling sorry for the new to the forum OP after........



you can fit 20 showers so long as not more than 1at a time is switched on.
other than that run them off a combi boiler for considerably better performance.

Thank you for expressing an opinion - you're the only one so far that has. Of the electricians I've discussed this with, answers range from "it must be 100a fuse", to "see how you get on with 60A (the existing one), if it blows they'll replace it free anyway".

Would have been interesting to see what others think.

 

[telectrix]

and what business have you altering the I N of the DNO bullit?chances are its a shared supply as well....

could be that DNO have offered 80A FOC.

 

[Callcom]

and what business have you altering the I N of the DNO bullit?

chances are its a shared supply as well....

It's not. VPN have quoted for the fuse upgrade - free if it's 80A, hence the question

 

[Gavin A]

I'm due to qualify as a domestic installer soon, and my brother, who is fully qualified, will be doing most of this work.

I have a 60A main fuse.
I currently have a typical domestic installation, i.e. cooker, immersion etc, and one electric shower.
Due to distances between hot/cold supply and downstairs bathroom, I want to fit an electric shower there too.
I'm also planning a new en-suite and want an electric shower there as well
i.e. 3 electric showers in total.

I can upgrade to 80A main fuse for free. 100A would cost nearly a grand.

Question: can I run 3 electric showers with an 80A main supply?

No.

AFAIK diversity is not allowed to be applied to electric showers, therefore you would have 98Amps being drawn by 3 x 7.5kW showers on an 80A bullet just from the showers, and that's with a low rated shower.

for 3 showers you really want to be fitting a cylinder... well, what I mean is, getting a plumber in to fit a cylinder and proper hot water system for you.

ps http://www.napitonline.com/downloads/CP 4 07 P 10-11 16th Diversity.pdf

ps working at home so not got the regs with me, but the OSG reference has been given to look it up yourself

 

[Callcom]

No.

AFAIK diversity is not allowed to be applied to electric showers, therefore you would have 98Amps being drawn by 3 x 7.5kW showers on an 80A bullet just from the showers, and that's with a low rated shower.

for 3 showers you really want to be fitting a cylinder... well, what I mean is, getting a plumber in to fit a cylinder and proper hot water system for you.

ps http://www.napitonline.com/downloads/CP 4 07 P 10-11 16th Diversity.pdf

ps working at home so not got the regs with me, but the OSG reference has been given to look it up yourself

Thanks Gavin, that's really helpful, I'll have a look at that. We do have a hot water system, oil-fired, but probably insufficient to run up to three showers as well as supply rest of house. Also pumped showers need a dedicated supply as you probably know and that's the problem - because of the house layout and distance to the showers, it would cost a fortune in plumbing terms.

Thanks again.

 

[guest119]

What is a qualified domestic installer? Do you work for Pickfords?


Boydy

 

[Kate]

Install a contactor switch, one supply from the db to the switch, wire all the showers from that. That way only one shower can operate at once.

 

[Callcom]

Install a contactor switch, one supply from the db to the switch, wire all the showers from that. That way only one shower can operate at once.

That's an interesting idea, thanks.

 

[trev]

Due to distances between hot/cold supply and downstairs bathroom, I want to fit an electric shower there too.

So this downstairs bathroom is pre existing and doesn't have a hot water supply?

 

[skippy2]

Like it or not that animal exists boydy, take the building regs exams and the regs exam and hey presto qualified domestic installer, register with the selected body of your choice and away you go if you are daft enough those with sense get in with a fully qualified sparkie and get experience before setting out on their own.

 

[Callcom]

So this downstairs bathroom is pre existing and doesn't have a hot water supply?

Yes, and it does - but to fit a shower pump you have to have a dedicated supply direct from storage tank & cylinder - Salamander Pumps even say you need a 28mm supply, not 22mm.

I could just use the existing 22mm hot and cold supply, which I think is what you are suggesting, but the risk is the pump cutting out due to low pressure if someone turns on a tap, etc. Also never getting a decent flow, which defeats the object.

 

[trev]

Withdrawn

 

[MDJ]

Great to see Trev back, a decent respectable electrician, as rare as rocking hores Sh*t on this forum of late lol

- - - Updated - - -

Like it or not that animal exists boydy, take the building regs exams and the regs exam and hey presto qualified domestic installer, register with the selected body of your choice and away you go if you are daft enough those with sense get in with a fully qualified sparkie and get experience before setting out on their own.

A made up name by the NICEIC, total balls.

 

[GLENNSPARK]

Great to see Trev back, a decent respectable electrician, as rare as rocking hores Sh*t on this forum of late lol

- - - Updated - - -

A made up name by the NICEIC, total balls.

its not just the NIC Mike...they all have a collective responsibility for this shambles...

ELECSA refer to their members (regardless of their quals and/or competancy) as elecsa approved contractors....i think napit have something similarly sinister...

like you NEED their approval or something....

 

[trev]

Great to see Trev back, a decent respectable electrician, as rare as rocking hores Sh*t on this forum of late

Thank ye sir

 

[guest119]

My missus gives me a pat on the back when Im going to work in the mornings. Does that mean I can call myself approved :ciappa:.


Boydy

 

[guest119]

Withdrawn

Thats never been the most reliable method Trev!

Boydy

 

[GLENNSPARK]

My missus gives me a pat on the back when Im going to work in the mornings. Does that mean I can call myself approved :ciappa:.


Boydy

return the complement when your tea arrives at the table..

 

[telectrix]

it matters little to me whether a guy has done a full apprenticeship or a electrical trainee course. if he's competent to work in his chosen field through practical and theoretical training, and works within the limits of his/her competence, then i have no problem with that. and i stress the word competence. tin hat on, runs for bunker.

 

[Kate]

That's an interesting idea, thanks.

I have done this on a previous job

 

[Octopus]

it matters little to me whether a guy has done a full apprenticeship or a electrical trainee course. if he's competent to work in his chosen field through practical and theoretical training, and works within the limits of his/her competence, then i have no problem with that. and i stress the word competence. tin hat on, runs for bunker.

As I've said before, some of the fully qualified time served 20+ year guys round here are the worst for dodgy, rushed, crxp jobs I see.

 

[Richard Burns]

You can get shower priority units that are popular in Ireland but not GB that do the same as Kate's excellent idea.
2NO and 2NC contactors could also be used but cost will escalate.
Also remember that even though diversity is not permitted a 60A fuse will take 98A for about 2.5 hours before blowing, so the fuse will not blow with ten minute showers even if they are all on at once, however if you can just make sure only 2 are on at any one time then an 80A fuse should suffice (if you have 7.5kW showers).

Plumbing is the best option as said many times above.

 

[Engineer54]

it matters little to me whether a guy has done a full apprenticeship or a electrical trainee course. if he's competent to work in his chosen field through practical and theoretical training, and works within the limits of his/her competence, then i have no problem with that. and i stress the word competence. tin hat on, runs for bunker.

Well said. ....Now pray tell me and every other time served electrician exactly HOW anyone can claim to be competent to work in a customers home after 17 to 20 days of classroom training??
You can't, ....because it's just NOT possible!! All that comes from those short days of training, are folk that are under trained, under qualified, under skilled, inexperienced wannabe's!! And it need to be STOPPED!!

 

[GLENNSPARK]

Well said. ....Now pray tell me and every other time served electrician exactly HOW anyone can claim to be competent to work in a customers home after 17 to 20 days of classroom training??
You can't, ....because it's just NOT possible!! All that comes from those short days of training, are folk that are under trained, under qualified, under skilled, inexperienced wannabe's!! And it need to be STOPPED!!

and if we all shove on in the right direction it will be n all....

takes the collective i dare say though on this one...

 

[Darkwood]

I too am bemused as to why the OP is on here if his brother who's doing most of the work is fully qualified why haven't you just asked him direct as it been mentioned in a few posts surely he is your first port of call or are we to assume he couldn't answer your question so you said you would put it on here?

Something doesn't add up here...

If the brother tale is just a fob off then i would rather than jump in at the deep end start on smaller installs and work your way up gaining experience through the journey.. TBH id start off with a wendy house and work your way up to a 5 bedroom set-up.

As your just barely walking out of the college or training course this really should be all still strong in your head although this isn't really about the question you asked its just things don't add up.

 

[Gavin A]

You can get shower priority units that are popular in Ireland but not GB that do the same as Kate's excellent idea.
2NO and 2NC contactors could also be used but cost will escalate.
Also remember that even though diversity is not permitted a 60A fuse will take 98A for about 2.5 hours before blowing, so the fuse will not blow with ten minute showers even if they are all on at once, however if you can just make sure only 2 are on at any one time then an 80A fuse should suffice (if you have 7.5kW showers).

Plumbing is the best option as said many times above.

True, but that was only the showers, add in all the other circuits in the house with diversity included and you'd probably be up to 140A or so, which would put it somewhere near the 18-20 minute mark for an 80A fuse, or well under 10 minutes for a 60A fuse (If I'm reading the right graph, having to search for it on google).

I suppose it probably would be something that could be got away with for quite a while, but sods law it'd be Christmas day with all the family home and the turkey in the oven that the fuse would pop.

eta - Not that I'm involved in this stuff really, so I might have got it wrong?

 

[Engineer54]

I might have got it wrong?

You have, ...big time!! lol!!

 

[Hawkmoon]

What people often forget when planning 'multiple' electrical showers is water pressure - this will limit simultaneous usage...

In my place a flushed toilet ferks up just the one shower! lol

 

[Badged01]

What people often forget when planning 'multiple' electrical showers is water pressure - this will limit simultaneous usage...

This is why you should leave installing and connecting up of electric showers to the professionals ...... plumbers!

 

[MDJ]

This is why you should leave installing and connecting up of electric showers to the professionals ...... plumbers!

I am reporting you to marvo for foul language lol

 

[Hawkmoon]

Install a contactor switch, one supply from the db to the switch, wire all the showers from that. That way only one shower can operate at once.

This sounds pretty complex...

Do you mean a contactor for each shower incorporating n/o & n/c contacts to break feeds (to other showers) as necessary?

Or am I missing something simpler?

Please explain

 

[MDJ]

This sounds pretty complex...

Do you mean a contactor for each shower incorporating n/o & n/c contacts to break feeds (to other showers) as necessary?

Or am I missing something simpler?

Please explain

Seems overkill doesn't it, if you need three showers in a house then I would ask the local provider for A 100 amp supply myself, Contactors whatever next, relays and start stop units in the lounge lol.

 

[Callcom]

You can get shower priority units that are popular in Ireland but not GB that do the same as Kate's excellent idea.
2NO and 2NC contactors could also be used but cost will escalate.
Also remember that even though diversity is not permitted a 60A fuse will take 98A for about 2.5 hours before blowing, so the fuse will not blow with ten minute showers even if they are all on at once, however if you can just make sure only 2 are on at any one time then an 80A fuse should suffice (if you have 7.5kW showers).

Plumbing is the best option as said many times above.

Thanks for your advice. Yes I had originally thought a pumped shower was what we would install, but given it has to have a dedicated, ideally 28mm supply, and the house layout/distance, that option proved prohibitively expensive.

 

[GLENNSPARK]

What people often forget when planning 'multiple' electrical showers is water pressure - this will limit simultaneous usage...

In my place a flushed toilet ferks up just the one shower! lol

this can have advantages...

such as just after arguments....

 

[Marvo]

Diversity is about common sense. I don't understand why the regs would say not to apply diversity to multiple showers when there could even possibly be a house where there's more showers than people.