night tariff meter change to standard tariff

[Colin188]

What you need to do, is get the DNO to remove the off peak meter and to have ready a dual isolator for them to connect the meter tails into.
Then you can connect both CUs into the dual isolator.
As Westward10 says, you will need to provide RCD protection for the sockets.

i think it would be easier if i can take the four 2.5mm t&e radial feeds from the economy 7 consumer unit and connect them to the main tariff consumer unit which has split load rcd and install 16 amp mcb for each radial circuit. this should cover all bases.

 

[westward10]

The op has not mentioned, whether the E7 CU has rcd protection.?It already may have.

It has not.

 

[westward10]

i think it would be easier if i can take the four 2.5mm t&e radial feeds from the economy 7 consumer unit and connect them to the main tariff consumer unit which has split load rcd and install 16 amp mcb for each radial circuit. this should cover all bases.

Yes if there are adequate spare ways.

 

[davesparks]

Another of the ill thought out changes to the regs..... If you don't have the knowledge to turn off two switches rather than one, words fail me

Changes? The requirement for a single main switch was in the first edition!

 

[Colin188]

Yes if there are adequate spare ways.

I should be able to take two spur circuits off each of the two 32amp ring main mcb in the consumer unit. The sockets will be single socket outlets.

 

[westward10]

I should be able to take two spur circuits off each of the two 32amp ring main mcb in the consumer unit. The sockets will be single socket outlets.

Not sure that is the greatest idea, four 2.5 conductors at one mcb.

 

[Deleted member 26818]

Lol.
I read it as being one spur from each RFC taken from the relevant MCB, so only 3 conductors?

 

[westward10]

He has four radials and two ring finals?

 

[Deleted member 26818]

Yes, I just assumed the OP would spur a single socket of each MCB and use a couple of spare ways for the other two.

 

[Colin188]

"537.1.4 A main linked switch or linked circuit-breaker shall be provided as near as practicable to the origin of every installation as a means of switching the supply on load and as a means of isolation.
A main switch intended for operation by ordinary persons, e.g. of a household or similar installation, shall interrupt both live conductors of a single-phase supply."

Just a reference on this.Hello,
Please offer clarification as to whether regulation 537.1.4, or in fact any other regulation prohibits the common practice of splitting the mains supply from the meter, via Henley block to 2 or more CCU's? Each CCU in its own right has DP isolation. Does this regulation, or in fact any other regulation insist on a suitably rated DP isolator to be placed in line with the meter tails offering a single point of isolation for the 2 or more separate CCU's.

Note, an assessment of general characteristics would additionally be conducted to ensure compliance.

This question needs a written answer as evidence to address the questions within my immediate circles, that the above practice of splitting the mains supply via Henley block doesn't comply with the Regs and specifically 537.1.4.

Thank you.

Regards,

NICEIC response:

Wango
Please accept our apologies for the delay in replying to your query.
I can confirm that such practice is allowed under BS 7671. Attention should also be given to 537.2.1.3 & 537.2.2.6
I hope this helps.
Regards
**** ***** BSc MIET IEng
Area Engineer

 

[westward10]

I totally disagree with this for a domestic installation, can they confirm where in BS7671 this is noted. I suspect they are implying that by doing this you are creating two installations each of which having a single point of isolation making Reg 537.1.4 a farce.

 

[snowhead]

As the installation is now and any other with split off peak, there is no single point of isolation other than the 2 C.Us being adjacent to each other.

 

[westward10]

Use a four pole isolator.

 

[Deleted member 26818]

As the installation is now and any other with split off peak, there is no single point of isolation other than the 2 C.Us being adjacent to each other.

Two installations.
The origin of an installation is and always has been, the customer connection point (usually at the meter).
With split tariffs there is either two meters, each supplying a separate installation or a single meter with two connection points, with each connection point supplying a separate installation.
BS7671 allows for more than one installation in a building.

The NICEIC (despite the fact that the respondent is a member of the IET), loves to make up their own regulations or make their own interpretation.

 

[Colin188]

I totally disagree with this for a domestic installation, can they confirm where in BS7671 this is noted. I suspect they are implying that by doing this you are creating two installations each of which having a single point of isolation making Reg 537.1.4 a farce.

I would assume that the double pole switch disconnections in each consumer unit would satisfy this as both consumer units are next to each other.

 

[westward10]

I would assume that the double pole switch disconnections in each consumer unit would satisfy this as both consumer units are next to each other.

I disagree but that aside how will you provide additional rcd protection.

 

[Deleted member 26818]

I would assume that the double pole switch disconnections in each consumer unit would satisfy this as both consumer units are next to each other.

No.
They comply at present because they are two separate installations, both controlled by a single point of isolation.

 

[Deleted member 26818]

The purpose of the single point of isolation, is so in the event of an emergency, the installation can be switched off easily.

 

[Colin188]

The purpose of the single point of isolation, is so in the event of an emergency, the installation can be switched off easily.

So with correct warning identification on each consumer unit this would meet requirements. If one cu was a shower cu then mark as shower, if next was garage cu then mark as garage, and the final cu would be marked main distribution i.e sockets/lighting making correct for emergency/maintenace isolation for the domestic consumer.

 

[Deleted member 26818]

That would be for you to decide.
In the event of a fire with smoke billowing around, would what you suggest be easy for a fire fighter who doesn't know the property, to isolate?