Rules and Guidelines
Want to participate in the discussions? Please read our Community Rules and Guidelines. Need some help? Visit Support and Answers.

  • State Not Answered
  • Locked Locked
  • Replies 60 replies
  • Subscribers 32 subscribers
  • Views 5799 views
  • Users 0 members are here
Options
You may also be interested in
This discussion has been locked.
You can no longer post new replies to this discussion. If you have a question you can start a new discussion

3-phase E7 meter on single phase supply?

Former Community Member
Former Community Member
My home is wired for storage heaters but none are fitted at the moment. I’ve been using a multi-fuel stove using mostly coal but I have decided to have storage heaters fitted for this winter. I have been with EON on their Heatwise tariff which gives off-peak hours 5 at night; 3 in afternoon and two in evening.. I have two consumer units  - one for normal rate and one for off-peak rate with only the immersion heater using off-peak at the moment.
EON have told me that I can’t have this old tariff anymore and so I agreed to move to their E7 tariff and have an E7 Smart Meter installed.
I currently have a single-phase incoming supply cable feeding two 100A fuses and two meters. One fuse feeds a normal rate meter and the other fuse feeds the off-peak meter. I don’t know why there are two meters fed by separate fuses and why the installation does not use the off-peak meter to record normal rate usage.
I discovered that the meter technician is not a qualified electrician and he didn’t know what to do so he phoned his supervisor who told him not to proceed with the meter change. I spoke to the supervisor on the phone and asked him why the one fuse cannot be removed and the remaining fuse can then supply the new E7 meter. He told me that I would have to get a qualified electrician to approve that which surprised me and I got the impression that these meter technicians don’t appear to know an awful lot.
The supervisor suggested that a 3-phase meter could be fitted retaining the two fuses and the meter is then fed by two cables although it is still a single phase supply. He also told me that the 3-phase meter would not be a Smart Meter. The meter technician was not qualified to do that but he could do the job himself so would phone me later to arrange it.
Another thing the supervisor told me was that I could only have four night storage heaters which I disagreed with explaining that I was proposing to have five which would add up to 17.22kw including the 3kw immersion element – equating to just over 70A and surely the limit is the total load and not the number? There is no electric shower fitted.
I don’t have a lot of confidence that these meter technicians know what they are doing and would have preferred a qualified electrician but EON don’t have any to do meter changes.

My question is does this sound ok or not please – can a 3-phase meter be fitted and fed by two cables from the incoming single-phase supply through the two fuses already fitted.  This all sounds a bit strange so any help appreciated so thanks for any comments.
1e7bf7c9788ef3dd52872a7568fabe12-huge-img_20201007_103219.jpg

Parents
  • Former Community Member
    0 Former Community Member
    mapj1:

    Given it is as you say " a modern small detached bungalow built about 1990 with modern wiring.  "

    So presumably insulated cavity walls, loft insulation, double glazing, porches on outside doors  etc.


    Has the 17kW design been done by someone allowing for the thermal envelope of the house ? I suspect that half that may be enough in practice.


    Yes, all well insulated as you suggest.


    I'm a retired mechanical design engineer and part of my college course included applied heat so I am able to design a central heating system by calculating the heat requirement for each room. The 17kw is my own design but was done using a 'ready reckoner' rather than using precise u-values. That does include 3kw for immersion element although that is in a well insulated tank and cycling on its stat.

    The difference in price between a 1.5kw and a 1.25kw heater is only about £40 and only about £100 more than a 1kw heater so I have erred on the larger size. If the heater doesn't need to charge to its capacity then it won't.


    As statter rightly says in response, the charge is only for 7 hours - I'll have anothe look at it but I think it's about right.


    Thanks for your comment - Nigel


     


Reply
  • Former Community Member
    0 Former Community Member
    mapj1:

    Given it is as you say " a modern small detached bungalow built about 1990 with modern wiring.  "

    So presumably insulated cavity walls, loft insulation, double glazing, porches on outside doors  etc.


    Has the 17kW design been done by someone allowing for the thermal envelope of the house ? I suspect that half that may be enough in practice.


    Yes, all well insulated as you suggest.


    I'm a retired mechanical design engineer and part of my college course included applied heat so I am able to design a central heating system by calculating the heat requirement for each room. The 17kw is my own design but was done using a 'ready reckoner' rather than using precise u-values. That does include 3kw for immersion element although that is in a well insulated tank and cycling on its stat.

    The difference in price between a 1.5kw and a 1.25kw heater is only about £40 and only about £100 more than a 1kw heater so I have erred on the larger size. If the heater doesn't need to charge to its capacity then it won't.


    As statter rightly says in response, the charge is only for 7 hours - I'll have anothe look at it but I think it's about right.


    Thanks for your comment - Nigel


     


Children
No Data

Community Rules & Guidelines