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Topic Title: Conversion of two terraces to one property
Topic Summary: Repercussions reference supplies on different phases
Created On: 31 October 2013 12:37 PM
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 31 October 2013 12:37 PM
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Thripster

Posts: 646
Joined: 22 August 2006

Hello, looking for advice regarding a customer who has knocked two adjacent terraced properties into one. He intends to keep the individualsupplies as was. Question is, what regulations/bye laws/repercussions are there to take account of two different supplies, possibly on different phases, within the one (now) property?

Regards
 31 October 2013 01:07 PM
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AJJewsbury

Posts: 11587
Joined: 13 August 2003

Different phases shouldn't be a problem at all - the wiring regs don't even require a voltage warning label any more.

Lack of single point of isolation might be more of a concern, especially if the two installations get intermingled. The DNO/fire service might have an objection on similar grounds.

I'd make sure that all the bonding is correctly sized - if it's PME you're likely to get diverted N currents favouring one service over the other.

Seems like an expensive solution, standing charges wise...

- Andy.
 31 October 2013 01:32 PM
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Thripster

Posts: 646
Joined: 22 August 2006

Thanks Andy. In the short term there will be no
Interconnection as the customer is competent so the two parts of the now one property are identifably separate. However, there is the concern on what happens on change of occupancy and, as you say, the charges for two supplies.

Regards
 31 October 2013 05:52 PM
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aligarjon

Posts: 2876
Joined: 09 September 2005

I wouldn't think it would be too expensive to just run a sub-main between the two and get the one disconnected.

Gary

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 31 October 2013 06:02 PM
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SKElectrical

Posts: 910
Joined: 01 February 2009

I have wondered in the past about similar circumstances of old Victorian houses converted into separate flats on different phases. Point of isolation is the main concern but a competent person will be well aware of this.
 01 November 2013 12:21 PM
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davethomas

Posts: 139
Joined: 09 January 2004

You haven't said that it is on 2 phases, and it may well not be: the traditional every third house on the same phase is, according to my son ( Scotiish Power Jointer), commonplace but by no means universal. Sometimes small blocks of houses are on one phase, so you'd need to check, as it may not be the case. However, I would agree that isolation is really your only main issue here. Granted, people in future could be capable of doing dangerous things by mixing supplies etc, but hey, that's always the case if you let incompetents loose, and rather beyond your control. Also, if there is RCD protection on all circuits at each CU, any unintentional mixing of supplies would just instantly trip anyway.
 01 November 2013 12:28 PM
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calumbtw

Posts: 28
Joined: 22 October 2012

Originally posted by: AJJewsbury

Different phases shouldn't be a problem at all - the wiring regs don't even require a voltage warning label any more.

- Andy.


Doesn't 514.10, tell you that you need warning notices where the nominal voltage exceeds 230V? I thought you required warning notices due to L-L voltage being 400V?

Do you know when this was taken out?

Thanks
 02 November 2013 12:35 AM
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aatomic69

Posts: 20
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I don't see a problem for this. I would assume that the the two property's were on dif phases.
Some property's have two different phase supply's when they have additional load requirements and need a three phase meter but only need two of the phases or I presume three phases wasn't an option.
You would be paying for 2 MPANS at the property so like someone said run a submain and have one meter disconnected.

It is common tho to see older neighbouring houses on the same phase. Either way get one meter disconnected.
 02 November 2013 12:09 PM
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alancapon

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Joined: 27 December 2005

As an electricity supplier, we would want to see one of the services removed, such that there is a single point of supply for the property.

Regards,

Alan.
 02 November 2013 02:34 PM
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Thripster

Posts: 646
Joined: 22 August 2006

Thank you for the comments. Alan, is that enforcable (ie: a requirement in law) or a condition of maintaining supply? At the moment an archway has been put in upstairs and another downstairs. That is the extent of knocking into one. The incomers are at the furthermost distance possible between each other. I am not defending the position but do need to know what to advise the customer. The work has been notified to the customer and he has said that the buding inspector has not mentioned anything.
 02 November 2013 02:38 PM
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Thripster

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Sorry, pushed 'reply' button before finishing/spell checking. Seems that the customer is keeping one side 'domestic' and the other for his girlfriend's aromatherapy business despite there being direct access between the two sides, top and bottom.

Regards
 02 November 2013 02:39 PM
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Thripster

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Notified to council
 03 November 2013 01:18 PM
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AdrianWint

Posts: 262
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Originally posted by: calumbtw

Originally posted by: AJJewsbury

Different phases shouldn't be a problem at all - the wiring regs don't even require a voltage warning label any more.

- Andy.


Doesn't 514.10, tell you that you need warning notices where the nominal voltage exceeds 230V? I thought you required warning notices due to L-L voltage being 400V?

Do you know when this was taken out?

Thanks


Nope. It tells you that you needed a label if the voltage to earth exceeded 230V. The fact that you have two phases which may well have 400V between them doesn't change the fact that each one is only 230V to earth.
 04 November 2013 01:40 PM
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AJJewsbury

Posts: 11587
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I thought you required warning notices due to L-L voltage being 400V?

Do you know when this was taken out?

It has a bit of a muddled history. I think it started with one of the 16th editions where they added it 'to earth' in the 1st paragraph (probably to bring us in line with the continent where large appliances (e.g. cookers) are typically 3-phase) , but left in a but left in a bit about between simultaneously accessible enclosures - which didn't make sense. It then took a couple more iterations to get it right - during which the regs and OSG seems to contradict each. It's been like that for a good few years now though.
- Andy.
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