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Will I need10 separate meters with a MSDB (Multi-Service Distribution Board)?

J
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Hello,

 

I am converting a property into 10 student accommodation flats.

 

A three-phase supply is required and we received an offer for an MSDB board 180KVA.

 

Today I was told by National Grid, that with an MSDB board we will require 10 separate meters in either the rooms or the communal areas.

 

As this will be student accommodation and all bills included, I'd rather have one meter positioned in the existing meter room.

 

National Grid told me that for this, only with a Cut Out will it be possible to have one meter only.

 

Can someone please help me out with this?

 

- What is the difference between a Cut Out and MSDB?

 

- How does the difference between the two impact the number of meters required?

 

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Best answer by Jeffus 10 May 2023, 08:24

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Jeffus
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Hi @Johnsmith1682 

Welcome to the customer forum, i am just a customer like you, not a qualified electrician. 

A cut out is basically the main fuse(s) you see in your home. These sit before your meter. Most homes are single phase, but 3 phase is becoming more common due to things like heat pumps and Electric Vehicle charging. 

https://www.ukpowernetworks.co.uk/help/what-is-a-cut-out

So with a cut out setup you only need one meter, albeit a 3 phase meter. You will find a lot of small scale student accommodation has this setup. 

This is a MSDB Multi Service Distribution Board setup for flats

https://www.beama.org.uk/static/8450cb4e-3c53-4a9a-8d2a8b6f04ff1bab/Technical-Bulletin-Safely-using-Multi-Service-Distribution-Boards.pdf

This splits the supply into multi circuits in your case for the 10 flats and common areas, before the meter, so you would then need a separate single phase meter for each of the 10 circuit/flat as per the diagram. So a fuse for one flat may blow, but the others may not. Also with 10 meters you will have 10 sets of standing charges. 

What option has your electrician recommend in line with any regulations? Either option is a possibility. 

Out of curiosity, are you planning on having a separate physical consumer unit for each flat, located within each flat, irrespective of which National Grid option you go with (Cut Out or MSDB)? 

If you post updates i am sure it will help other customers on the forum going forward. 

BPLightlog
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Hi @Johnsmith1682 what is most likely meant is that each separate feed will need some sort of isolation device (or cut out) located in or near each accommodation. This is for safety so that any supply can be cut quickly. 
Depending on the layout and circuits involved, it may be that a distribution board with isolation switch in each part would suffice. The idea is that it’s not wired traditionally in a ring as that gives two supply paths. 
As always you should contact a professional electrician or seek advice from the NIC

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J
Rank

Hello guys thank you for clarifying…

 

This will be 10 student accommodation studios with all bills included - hence why I am against having 10 meters installed in rooms and common areas.

 

Yes we will be having consumer units in every room irrespective of which option we go for.

 

I'm assuming with consumer units this removes the need for an MSDB?

 

 

BPLightlog
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You need to double check but here is a sub db in a separate building on site.
 

This also has a cut out (isolator) at the main feed

 

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J
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You need to double check but here is a sub db in a separate building on site.
 

This also has a cut out (isolator) at the main feed

 

Is the first image a consumer unit?

BPLightlog
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Is the first image a consumer unit?

Yes, just a mini one as it feeds a small shower room, utility space. 

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J
Rank

Thanks for this, just to aid my understanding a little bit more…

 

National Grid:

- Told on application it will be 10 self contained flats

- They offered MSDB with 10 separate connections but need 10 separate meters

- Large Cut Out but with CT panel and half hour metering

 

I think I understand the confusion ^ , they are advising on the basis of the wrong information assuming that each flat is separate ownership.

 

Instead…

 

10 Student Accommodation Studios:

- All bills included

- No desire for separate billing

- Consumer units in every room

 

MSDB or Cut Out?

 

Cut Out - you are suggesting that we can have a cut out and since the consumer units will already be in every room this should provide sufficient isolation. Therefore we won't require half hour meters or a CT panel?

 

MSDB - as per above diagram, this will have 10 consumer units, but will it still require 10 separate billing meters?

 

BPLightlog
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From what I understand (and none of us can give definitive advice) with each accommodation having its own ‘consumer’ unit (or distribution board) and an isolator, the safety part of those circuits is satisfied. 
What may still be necessary is an isolation point from the main feed so that if a problem occurs between the meter and one of the consumer units, that can also be isolated. You might be able to do this with a bank of MCB’s
There are specific parts of the Wiring Regulations (currently 18th edition and BS7671) that relate to this type of installation and this would need to be satisfied for certification 

Independent volunteer - Sitting in a Faraday cage, waiting for a signal
J
Rank

Hi @Johnsmith1682 

Welcome to the customer forum, i am just a customer like you, not a qualified electrician. 

A cut out is basically the main fuse(s) you see in your home. These sit before your meter. Most homes are single phase, but 3 phase is becoming more common due to things like heat pumps and Electric Vehicle charging. 

https://www.ukpowernetworks.co.uk/help/what-is-a-cut-out

So with a cut out setup you only need one meter, albeit a 3 phase meter. You will find a lot of small scale student accommodation has this setup. 

This is a MSDB Multi Service Distribution Board setup for flats

https://www.beama.org.uk/static/8450cb4e-3c53-4a9a-8d2a8b6f04ff1bab/Technical-Bulletin-Safely-using-Multi-Service-Distribution-Boards.pdf

This splits the supply into multi circuits in your case for the 10 flats and common areas, before the meter, so you would then need a separate single phase meter for each of the 10 circuit/flat as per the diagram. So a fuse for one flat may blow, but the others may not. Also with 10 meters you will have 10 sets of standing charges. 

What option has your electrician recommend in line with any regulations? Either option is a possibility. 

Out of curiosity, are you planning on having a separate physical consumer unit for each flat, located within each flat, irrespective of which National Grid option you go with (Cut Out or MSDB)? 

If you post updates i am sure it will help other customers on the forum going forward. 

 

 

Hello,

 

I can confirm we are now going with a 3 phase cut out for our property, each room will have its own consumer unit.

 

However, National Grid have told us that with a 3 phase cut out we will require a CT panel and half hour billing.

 

Can you or anyone else advise on the reason we would require this?

BPLightlog
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Hi @Johnsmith1682 the CT will be for the meter - many of this type connect via CT. 
As to the half hour billing, it is becoming a default but I would guess that is just to set up the best tariff options. 

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J
Rank

Thank you,

 

Can you explain to me why a CT panel is required? what exactly does it do?

BPLightlog
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Thank you,

 

Can you explain to me why a CT panel is required? what exactly does it do?

A CT is a current transformer which measures the current flowing in a cable by clamping around the cable rather than directly. When large supply levels are involved, it is safer to use this technique. Being a 3 phase system, you will have 3 CT’s which presumably will be enclosed in their own separate panel. 
There is a code of practice for high supply levels (which your situation may need to comply with) known as COP5. 
Edit: actually just re-reading your first post, being 180KVA will have to comply with COP5

There are several companies offering enclosures for this type of installation 

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