The IET is carrying out some important updates between 17-30 April and all of our websites will be view only. For more information, read this Announcement

This discussion is locked.
You cannot post a reply to this discussion. If you have a question 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
    Chris Pearson: Good point about the fuse rating - I had assumed that because the fuse holder stated 100A then that was the fuse rating.


    I've never had the installation inspected or tested and don't know anyone who has? The building is modern built about 1990 and both Consumer Units have MCB with RCD protection. I've lived here about 20 years and don't get any tripping apart from once when immersion element failed and gave earth fault. I have been thinking of moving and intend getting the installation tested and a safety certificate issued to offer when property is for sale just as I will get chimney swept and a certificate that flue is ok. Not a legal requrement but helps sale.

    *********************************************************************************************************************************************************************

    AJJewsbury: Thanks for that - yes, the normal meter is same rate at night unlike E7

    ************************************************************************************************

    mapj1: The building is a modern small detached bungalow built about 1990 with modern wiring.  Thanks for info but I can't see MPAN number but yes, I pay standing charge on both meters.

    *************************************************

    Sparkingchip: Thanks for info on 3-phase. EON say I can't keep the tariff I'm on as it is discontinued. Yes, understood about fuse rating but my calc of about 70 amps max does assume all heaters and immersion are on load continuously for 7 hours which I undestand is the correct assumption to make but in practice they won't be so 80A fuse would probably be ok.? I don't want to install a wet CH system, I think the future is electric and provided by renewables. Low maintenance and no servicing. A friend of mine has just upgraded to Dimplex XLE and they are still giving out heat when he goes to bed so he's really pleased with them

    *************************************************************

    Simon Barker: Yes, I suggested that the one fuse be removed and the new E7 meter be supplied by the existing single-phase through one fuse but was told they would not do that. Point taken about cost of electricity  but the 70A would not be drawn for the full 7 hours so not sure what cost wil be. I currently pay £600 per year for coal which is only used for about 20 weeks.

    *******************

    Finally, a big thank you for all the comments, advice and suggestions  and I've just has some good news. The supervisor who I spoke to on the phone has just phoned and he has spoken to his manager. He has retracted the suggestion of a 3-phase meter as they now don't think that would work! They have agreed to fit a new E7 Smart Meter supplied by the existing incoming single-phase cable through one of the board fuses. He agrees with you guys that it may not be a 100A fuse as I had assumed but I can get that upgraded by Western Power if needed.


    One final question out of interest about the incoming supply cable - what is the current rating of that? It measures about 15mm dia.

    Thanks - Nigel

Reply
  • Former Community Member
    0 Former Community Member
    Chris Pearson: Good point about the fuse rating - I had assumed that because the fuse holder stated 100A then that was the fuse rating.


    I've never had the installation inspected or tested and don't know anyone who has? The building is modern built about 1990 and both Consumer Units have MCB with RCD protection. I've lived here about 20 years and don't get any tripping apart from once when immersion element failed and gave earth fault. I have been thinking of moving and intend getting the installation tested and a safety certificate issued to offer when property is for sale just as I will get chimney swept and a certificate that flue is ok. Not a legal requrement but helps sale.

    *********************************************************************************************************************************************************************

    AJJewsbury: Thanks for that - yes, the normal meter is same rate at night unlike E7

    ************************************************************************************************

    mapj1: The building is a modern small detached bungalow built about 1990 with modern wiring.  Thanks for info but I can't see MPAN number but yes, I pay standing charge on both meters.

    *************************************************

    Sparkingchip: Thanks for info on 3-phase. EON say I can't keep the tariff I'm on as it is discontinued. Yes, understood about fuse rating but my calc of about 70 amps max does assume all heaters and immersion are on load continuously for 7 hours which I undestand is the correct assumption to make but in practice they won't be so 80A fuse would probably be ok.? I don't want to install a wet CH system, I think the future is electric and provided by renewables. Low maintenance and no servicing. A friend of mine has just upgraded to Dimplex XLE and they are still giving out heat when he goes to bed so he's really pleased with them

    *************************************************************

    Simon Barker: Yes, I suggested that the one fuse be removed and the new E7 meter be supplied by the existing single-phase through one fuse but was told they would not do that. Point taken about cost of electricity  but the 70A would not be drawn for the full 7 hours so not sure what cost wil be. I currently pay £600 per year for coal which is only used for about 20 weeks.

    *******************

    Finally, a big thank you for all the comments, advice and suggestions  and I've just has some good news. The supervisor who I spoke to on the phone has just phoned and he has spoken to his manager. He has retracted the suggestion of a 3-phase meter as they now don't think that would work! They have agreed to fit a new E7 Smart Meter supplied by the existing incoming single-phase cable through one of the board fuses. He agrees with you guys that it may not be a 100A fuse as I had assumed but I can get that upgraded by Western Power if needed.


    One final question out of interest about the incoming supply cable - what is the current rating of that? It measures about 15mm dia.

    Thanks - Nigel

Children
No Data