Advertisement
If you have a new account but are having problems posting or verifying your account, please email us on hello@boards.ie for help. Thanks :)
Hello all! Please ensure that you are posting a new thread or question in the appropriate forum. The Feedback forum is overwhelmed with questions that are having to be moved elsewhere. If you need help to verify your account contact hello@boards.ie

Showers on 5 core cable?

Options
  • 10-02-2020 4:16pm
    #1
    cgarrad
    Registered Users Posts: 1,611 ✭✭✭


    I'm building a house and have 3 en suites which all touch each other.

    3 instant showers 9kw each.

    House will have three phase.

    Can the electrcian wire them with 5 core 10mm or will it need 3 lenghts of 10mm t&e?

    BIG difference in price for the cable.


«13

Comments

  • Options
    #2
    2011
    Moderators, Home & Garden Moderators, Technology & Internet Moderators, Regional East Moderators Posts: 12,536 Mod ✭✭✭✭2011


    Each shower is an independent single phase load. As such it would make sense to have a cable per load. If you had a 3 phase load then a 5 core may make sense.

    The cable for each shower should be sized separately. It may not necessarily be a 10 sq. depending on a few factors (such as length of run) a larger cable size may be required.


  • Options
    #3
    cgarrad
    Registered Users Posts: 1,611 ✭✭✭cgarrad


    The run length (15m x 3) is the reason I wanted to try and reduce the cable cost ;-D

    So it's a definite no?


  • Options
    #4
    2011
    Moderators, Home & Garden Moderators, Technology & Internet Moderators, Regional East Moderators Posts: 12,536 Mod ✭✭✭✭2011


    cgarrad wrote: »
    The run length (15m x 3) is the reason I wanted to try and reduce the cable cost ;-D

    So it's a definite no?

    How do you propose to terminate a 5 core 10 sq. cable at the isolator for the first shower ?
    You won’t have enough terminals or space.


  • Options
    #5
    TheBully
    Registered Users Posts: 876 ✭✭✭TheBully


    Can I ask why your putting in a 3 phase connection? Are you running a guesthouse or something where there is potential to run 3 showers together?

    Sorry I know I’m not helping just curious


  • Options
    #6
    TheBoyConor
    Closed Accounts Posts: 3,292 ✭✭✭TheBoyConor


    Unless you have a very, very good reason to justify putting in 3p, then you should not be doing it. It costs substantially more in the long run.


  • Advertisement
  • Options
    #7
    TheBully
    Registered Users Posts: 876 ✭✭✭TheBully


    2011 wrote: »
    How do you propose to terminate a 5 core 10 sq. cable at the isolator for the first shower ?
    You won’t have enough terminals or space.

    This could work if he put a sub board up outside one of the bedrooms but would look pretty crappy. And just ran the 10sq t+e from there but if it was my house I know what I’d be doing.

    Also if cable ever fails you now have zero working showers


  • Options
    #8
    Xwebstar
    Closed Accounts Posts: 75 ✭✭Xwebstar


    TheBully wrote: »
    This could work if he put a sub board up outside one of the bedrooms but would look pretty crappy. And just ran the 10sq t+e from there but if it was my house I know what I’d be doing.

    Also if cable ever fails you now have zero working showers

    The cable wont fail but there's no saving when you factor in a sub-board and the 3P cable has to be protected at the Main DB too


  • Options
    #9
    2011
    Moderators, Home & Garden Moderators, Technology & Internet Moderators, Regional East Moderators Posts: 12,536 Mod ✭✭✭✭2011


    TheBully wrote: »
    This could work if he put a sub board up outside one of the bedrooms but would look pretty crappy. And just ran the 10sq t+e from there but if it was my house I know what I’d be doing.

    True.
    But as the cable runs are only 15m it is hardly worth it.


  • Options
    #10
    TheBoyConor
    Closed Accounts Posts: 3,292 ✭✭✭TheBoyConor


    Better off running 3 cables.

    A subboard introduces more complexity, additional components and more joints/connections - all additional potential failure points.

    Keep it simple stupid. Even if it does cost a bit more on cable. Sure the subboard and the labour of installing it all will eat up any saving on cable costs. It is only 15 meters anyway.

    Also, the heat will dissipate from 3 seaparate cables much easier than a 5 core one.


  • Options
    #11
    cgarrad
    Registered Users Posts: 1,611 ✭✭✭cgarrad


    TheBully wrote: »
    Can I ask why your putting in a 3 phase connection? Are you running a guesthouse or something where there is potential to run 3 showers together?

    Sorry I know I’m not helping just curious

    Was going with future proof, electric car and 3 showers. Think a lot of people will want it in a few years.


  • Advertisement
  • Options
    #12
    Xwebstar
    Closed Accounts Posts: 75 ✭✭Xwebstar


    Who's idea was this anyhow, there's no big saving on 45m of cable

    Sure leave out the earthrod and the main isolator they're hardly ever used


  • Options
    #13
    dazed+confused
    Registered Users Posts: 1,001 ✭✭✭dazed+confused


    On one side there seems to be crazy spending here and penny pinching on another.

    I would relook at your priorities.

    As stated already, avoid three phase at all costs and I would also recommend a maximum of two instant showers in a house.


  • Options
    #14
    TheBoyConor
    Closed Accounts Posts: 3,292 ✭✭✭TheBoyConor


    What is the reason for 3 instant showers anyway?

    Would it not make no sense to make the main bathroom an instant shower, then mixer showers in the ensuites.

    The ensuites will eb the ones most likely to be used at planned predictable times for which the HWC will be at temperature. Then for the unpredicatbel showers, visitors etc, they can use the instant shower.

    Electric showers are very expensive to run.

    Also, no power, no shower. Remember that. If you have a stove or whatever, your mixer showers will still work grand, albeit by candle light.


  • Options
    #15
    Xwebstar
    Closed Accounts Posts: 75 ✭✭Xwebstar


    I'm assuming op is making provision for car charging and maybe 3P heat pumps etc.


  • Options
    #16
    Xwebstar
    Closed Accounts Posts: 75 ✭✭Xwebstar


    An instantaneous electric shower on each phase of a domestic supply was all the fashion


    About 20 years ago..


  • Options
    #17
    TheBoyConor
    Closed Accounts Posts: 3,292 ✭✭✭TheBoyConor


    I can't see that ESB will be willing to install 3p supplies into private dwellings into the future. The demand it would place on the grid would be too great.


  • Options
    #18
    TheBully
    Registered Users Posts: 876 ✭✭✭TheBully


    TheBoyConor wrote: »
    I can't see that ESB will be willing to install 3p supplies into private dwellings into the future. The demand it would place on the grid would be too great.

    They will give it to you no problem if your willing to pay for it, nobody in their right mind would install it just for a few showers in this day and age though


  • Options
    #19
    Tuco88
    Registered Users Posts: 1,052 ✭✭✭Tuco88


    Are you allowed to use a common neutral over 3 showers like that? I wouldn't see it as good practice.


  • Options
    #20
    listermint
    Registered Users Posts: 33,697 ✭✭✭✭listermint


    Tbh whatever about the showers 3 phase may well be the future in construction. With the move to electrical based heating and of course the vehicles as pointed out. The expense in the long run is old thinking.


  • Options
    #21
    slavetothegrind
    Registered Users Posts: 2,789 ✭✭✭slavetothegrind


    You should really look at a plumbing solution here, much more cost effective in the long run.
    A pumped hot water supply to all three showers from afully insulated pressurised cylinder, even an electrically heated one, is a better solution.
    And only 6kw.


  • Advertisement
  • Options
    #22
    Xwebstar
    Closed Accounts Posts: 75 ✭✭Xwebstar


    Tuco88 wrote: »
    Are you allowed to use a common neutral over 3 showers like that? I wouldn't see it as good practice.

    I don't think there's any regulations that say you can't

    No benefit over 15m runs


  • Options
    #23
    listermint
    Registered Users Posts: 33,697 ✭✭✭✭listermint


    slavetothegrind wrote: »
    You should really look at a plumbing solution here, much more cost effective in the long run.
    A pumped hot water supply to all three showers from afully insulated pressurised cylinder, even an electrically heated one, is a better solution.
    And only 6kw.

    Not only better. But much nicer shower to use tbh. Thermostatic heads. Like a hotel.

    Tbh I don't like electric showers and I've had a few and have a brand new silent Triton there. It's nothing in comparison to my pumped system.


  • Options
    #24
    Sleeper12
    Registered Users Posts: 16,913 ✭✭✭✭Sleeper12


    I'm in the shower repair business. Electric showers are 90 percent of my business. They are a wonderful invention. Very handy not having to heat a tank of water before getting into the shower. A energy rated. Cheaper to have a 10 minute shower in this than heating water in the cylinder by immersion or by gas. You use less water. So many positives but but they are a compromise at best.

    There is nothing like a power shower. Yes you have to heat the water first, you use more water & it's not as cheap to run as an electric shower but it's invigorating. If I were you I'd have at least One of the showers on a bar mixer. with a diverter to a rain head & connected to a 2 or 3 bar pump. At least one & maybe Two. I definitely wouldn't have Three electric showers in the house. One or maybe Two. Install a priority board so only one can be used at a time & forget about 3 Phase. There are thousands of homes in Ireland manage perfectly with an EV & electric shower without issue

    If you go down the road of Three phase you will save very little by not running three separate cables. Not a sparks here bet there is something in the regs saying that an electric shower must have it's own dedicated supply. You can't connect a bathroom fan to the supply for exapmle. I've no idea if sharing the neutral would break this rule or not. Plenty of good skarks here can answer that better than me.


  • Options
    #25
    Bruthal
    Closed Accounts Posts: 13,422 ✭✭✭✭Bruthal


    Sharing the neutral won't overload the neutral anyway. Current will be that of 1 shower with 2 showers on and be 0 with 3.

    But 3 showers over 3 phases should be single phase circuits.


  • Options
    #26
    Tuco88
    Registered Users Posts: 1,052 ✭✭✭Tuco88


    Id be more worried with the common neutral getting broken. Less risk with a separate cable for each one.


  • Options
    #27
    Xwebstar
    Closed Accounts Posts: 75 ✭✭Xwebstar


    That risk is there for a 3P sub-board or panel in any type of installation with 1P loads

    Certainly better to avoid the sub-board here as there is no need for it


  • Options
    #28
    JL spark
    Registered Users Posts: 195 ✭✭JL spark


    3 phase heat pump / Air to water ,
    Showers off that with a central pump for pressure, by far the best solution in my opinion,


  • Options
    #29
    Bruthal
    Closed Accounts Posts: 13,422 ✭✭✭✭Bruthal


    Tuco88 wrote: »
    Id be more worried with the common neutral getting broken. Less risk with a separate cable for each one.

    It wouldn't be a huge issue probably. Self monitoring etc.

    Although not ideal if one shower was on cold only


  • Options
    #30
    Tuco88
    Registered Users Posts: 1,052 ✭✭✭Tuco88


    Would a 3phase RCD still work correctly in such case?

    5 Core cable one phase for each shower and shared neutral across the 3...


  • Advertisement
  • Options
    #31
    Xwebstar
    Closed Accounts Posts: 75 ✭✭Xwebstar


    Tuco88 wrote: »
    Would a 3phase RCD still work correctly in such case?

    5 Core cable one phase for each shower and shared neutral across the 3...

    It's not allowed or not recommended

    I can't recall which


Advertisement