re-wire imminent - some questions, any help appreciated

[bludclot]

I have been tasked with the re-wire a large property local to me. Seeing as it's a few years since i passed my 16th Edition and Part P and completed my last re-wire I need some help with the current state of play.

(I am not registered with ELECSA or similar, I will have to get my tester calibrated forthwith!)

From memory I have to submit a plan to my local council building control, complete the work and submit test results to them. Any change to this?

It's currently a PME system to a cellar located consumer unit. Customer requirements are for 2 further consumer units on higher floors of the property with separate meters to each unit so that lodgers can be charged an appropriate fee for their electricity usage (but she wants just a single bill to the property based on the main meter in the cellar) and so that any fault on either 'secondary' consumer unit does not trip her 'primary' RCD. Do I run 16mm singles from a non-RCD protected breaker in the main unit to feed RCD protected secondary consumer units? Or put 2 units in the cellar, one just to feed the secondary units?

Any product suggestions for the 'secondary' unit metering?

Any help appreciated, thanks.

 

[sparkiemike]

I have been tasked with the re-wire a large property local to me. Seeing as it's a few years since i passed my 16th Edition and Part P and completed my last re-wire I need some help with the current state of play.

(I am not registered with ELECSA or similar, I will have to get my tester calibrated forthwith!)

From memory I have to submit a plan to my local council building control, complete the work and submit test results to them. Any change to this?

There is a new part P document that you can should read. You don't need to submit a plan, but will need to notify them 48 hours before you start.

It's currently a PME system to a cellar located consumer unit. Customer requirements are for 2 further consumer units on higher floors of the property with separate meters to each unit so that lodgers can be charged an appropriate fee for their electricity usage (but she wants just a single bill to the property based on the main meter in the cellar) and so that any fault on either 'secondary' consumer unit does not trip her 'primary' RCD. Do I run 16mm singles from a non-RCD protected breaker in the main unit to feed RCD protected secondary consumer units? Or put 2 units in the cellar, one just to feed the secondary units?

Any product suggestions for the 'secondary' unit metering?

Any help appreciated, thanks.

Make sure your eathing and bonding arrangements are adquate for the building and flats - so that will probably mean at least a 10mm earthing conductor to the flats.

I would inclined to use switch fuses and SWA as the "sub-mains", then you would not have the RCD issue.

You can purchase meters from most wholesalers and online as well.

 

[viewer]

You need to check on what is required by LA and fire officer. The power to smoke/fire alarms and emergency lighting may currently be floor by floor so simply using a fused sub main to a meter may (or may not) be acceptable. Staircase lighting needs consideration both for practical wiring, but also for allocation of costs to avoid future landlord/tenant arguments.

 

[Taylortwocities]

You must not have a single point of failure.
A "primary" RCD is not a good idea.
See sparkiemike's post.

And also, and RCD should not be used as a main switch in the individual flats either.

I guess the separate meters would be in the "landlord's cellar"?

 

[bludclot]

Brilliant, thank you.

The property is not divided into flats, there is only one entrance. It's a large Victorian family house but to help pay the mortgage the top two floors are let to lodgers on a casual basis rather than separate flats, tenants and tenant agreements. There is however a bathroom and kitchen on each of the upper floors as well as the main family bathroom and kitchen on the ground floor. (We'll be re-fitting all these once re-wired and re-plumbed.)

Due to this I hadn't really considered running SWA to the upper floor consumer units.

Just suppose I installed an RCD in the cellar and ran from this to the upper floor consumer units, also RCD, should a fault trip the 'secondary' RCD and leave the 'primary' RCD still live?

I like the idea of switch fuse protected cables to the upper floors, that would work too.

I'll read the new Part P document as soon as I can.

 

[viewer]

Sorry to be a PITA and it isn't your problem, but to cover yourself I'd mention in writing to the owner that once separate electricity billing is introduced then the people living on the upper floors are no longer lodgers. Indeed with separate bathrooms and kitchens they are already tenants as they do not live as a part of a family. This is a house in multiple occupation and must comply with relevant legislation. The one entrance suggests one staircase and thus serious fire escape considerations especially with separate kitchens.
Whilst you have taken on the responsibility for dealing with building regulations with regards to the electrical work, this should really be part of a complete application and by doing the work without taking into account the non-electrical considerations you may be breaking the law and could lose a lot of time and money.

 

[bludclot]

hmmm yes that's food for thought. There's separate billing currently, this is to be done away with for a single bill so that the owner can have an idea as to where her electricity usage is going and then set lodging rates accordingly.

However I do think that there will be various paperwork trails on this one as you suggest. Luckily it's not my overall job, I'm just re-wiring!

 

[Taylortwocities]

I'll read the new Part P document as soon as I can.

You should do this FIRST and BS7671 too. I am concerned that you do not have the competency to carry out this job.

I hadn't really considered running SWA to the upper floor consumer units.
.

If teh cables are less than 50mm from the surface then that is the option if the cabling is not RCD protected, and you won't be able to do that (see below). Is there not a 'riser' space that the cables can go in to?

Just suppose I installed an RCD in the cellar and ran from this to the upper floor consumer units, also RCD, should a fault trip the 'secondary' RCD and leave the 'primary' RCD still live?

.

If you have two RCDs in series then the first RCD to trip will be the one with the faster trip time, and this can vary depending on where the sine wave is at the time of tripping.
The only way to ensure RCD A trips before RCD B is for RCD B to be a time delayed RCD. But that may not provide the protection required for your cables.

The key thing is this: you must not have a single point of failure.
\Suppose the "primary" RCD trips. All power to the building is now disconnected. , The tenants would have to find their way downstairs, into the cellar IN THE DARK, to reset the RCD. And if it is a hard fault then nobody has any power.

It wont work.

I suppose the emergency lighting and smoke alarm provision is part of the plan?

 

[bernardgreen]

Luckily it's not my overall job, I'm just re-wiring!

But you will be the person responsible for the electrical installation, you need to ensure that it is safe and is fit for purpose. When you sign the certification you will be making a legal statement that it is safe and fit for purpose. You therefore need to know and have proof that the house is either a single family dwelling or a House of Multiple Occupancy ( HMO ).

The laws about HMOs set minimum standards of electrical functions as well as electrical safety. They include functional fire alarms and emergency lighting for escape routes.

The bottom line is if you wire it as a single family dwelling but the council later discover ( or decide ) it is an HMO you may need to show why you wired it as a single family dwelling. The sub meters will strongly suggest you knew it was an HMO. If it is discovered to be an HMO after an incident involving fire and / or injury then you will be contacting your insurers

 

[Taylortwocities]

The local authority will be aware if the HMO because they will be inspecting his wiring at various stages, as part of the DIY building regs application.

 

[bludclot]

Thanks again for the replies.

This is a family house and not an HMO. The top floor is a lodger (a single female currently), the next floor down is the elderly father that the family receive a caring grant for i.e. effectively a lodger. When the father passes another lodger may be taken on to help with mortgage payments, this is to be decided when the time comes.

A good man knows his limits and to Taylortwocities I would suggest that by asking the relevant questions and finding the correct answers this demonstrates intellectual competency. I can produce my certificates to prove practical competency. I have been undertaking electrical work for years but my recently retired work partner undertook the testing and certificating. Now that role passes to me. We all start somewhere!

Anyway, thanks for the RCD in series information, yes that is inherently obvious when spelt out that clearly - a great piece of posting and a demonstration of how useful forums can be! The owner specifically stated journyes to the cellar to reset RCDs must be stopped with the new installation.

So what's the best method of taking power from the incoming meter tails to the upper floor consumer units? I wouldn't particularly want to install a non-device protected SWA through the property would I?

Mains powered battery back-up smoke alarms will be installed. No emergency lighting is planned, should this be added?

 

[ban-all-sheds]

bludclot - please accept the fact that your knowledge is too out of date and too limited for you to do this job - it cannot be done on the basis of you asking whatever random questions happen to occur to you as realise there are things you don't know.

 

[bludclot]

Point taken. A napit registered electrician has been brought in to specify components and undertake the testing and certification.

 

[SimonH2]

This is a family house and not an HMO. The top floor is a lodger (a single female currently), the next floor down is the elderly father that the family receive a caring grant for i.e. effectively a lodger. When the father passes another lodger may be taken on to help with mortgage payments, this is to be decided when the time comes.

Sorry, but you seem to be describing an HMO quite well. Just saying that it isn't one doesn't alter that.

What is an HMO ?
• at least 3 tenants live there, forming more than 1 household
Yup, most definitely from your description.

* you share toilet, bathroom or kitchen facilities with other tenants
That's less clear. If, and only if, each set of accommodation has it's own dedicated facilities, and other occupiers cannot use them - only then would it not be an HMO. If each 'home' had it's own front door within the building then it would be clear, but as it is then it's far from clear cut.


As pointed out, there are many rules and regulations that apply to HMOs but not to other types of property. And "significant" penalties for breaching them.


BTW - the owner should really read up on letting law - letting a room/suite as described with no tenancy agreement really is asking for trouble. Whatever the status of the lodgers, there are tax implications (the owner needs to notify HMRC of their letting business). If they take deposits then there are regs on protecting the deposit, criminal act as well as significant let related hassles for breaches - for example, if the deposit isn't legally protected then the landlord loses the right to evict the tenant with a "Section21" notice and for good measure the tenant can sue any time up to 6 years after the tenancy ends. Then the gas safety regs require that the boiler be on a maintenance agreement and the gas installation and all appliances must be tested ever 12 months. And so the list goes on.
From what you've written, it sounds like the owner may have overlooked some aspects ...

EDIT: This document also includes "A converted building containing one or more units of accommodation that do not consist entirely of self-contained flats. (There is no requirement that the occupiers share facilities)" which your description definitely meets.

 

[EFLImpudence]

This is a family house and not an HMO. The top floor is a lodger (a single female currently), the next floor down is the elderly father that the family receive a caring grant for i.e. effectively a lodger. When the father passes another lodger may be taken on to help with mortgage payments, this is to be decided when the time comes.

Sorry, but you seem to be describing an HMO quite well. Just saying that it isn't one doesn't alter that.

What is an HMO ?
• at least 3 tenants live there, forming more than 1 household
Yup, most definitely from your description.

Why?

There is only one lodger who has separate facilities.
Even if you count the father as a lodger (why?) that's only two.