Inexperienced in house rewires. Guidance needed.

[OhmSweetOhm]

Hi people,

Gonna rewire my house in the forthcoming weeks but I myself work on commercial and industrial projects and have only newly wired houses as an apprentice 2-3 year ago so I am unfamiliar with what should and shouldn't be done in house rewires.
I plan to use this thread for any advice that you lot would like to offer and for myself to ask any questions which I happen to think of!

So my first few are...

• Should outside sockets be part of a ring main or should they be spurred off a ring main?
• Does a boiler require it's own dedicated circuit?
• Is it legal to run cables behind skirting boards or must they be run underneath the floorboards and chased into the walls?

Thanks, appreciate it!

 

[Guitarist]

I've not had any dealings with them at all.

I just remember seeing them advertised when they first hit the market a few years ago, & seem to remember them being 6kw.

I work with a Heating Engineering firm and for a standard 2 bed house using the boiler for heating and hot water (combi replacement) the standard size is 8-10kw. 3-4 bed are usually 12kw. All depends on the thermal efficiency of the property of course, and if you have an electric shower as well, a boiler with an auto switch-off should be installed on the larger sizes.
Got an awkward decision atm, as the firm want to fit a 10kw without an inhibitor, and the lady wants an 8.5kw shower as well, so potentially pulling around 80A with a mains supply fuse of 100A. I realise this fuse will run at a lot more than 100A anyway, but not the best of situations.

 

[Darkwood]

Just throw my pennenth in re' the boiler on its own dedicated circuit...

If possible yes always rcbo dedicated.
If existing set-up or financial restrictions dont allow then acceptable to spur of the ring
If its a full rewire then always seperate rcbo as its within the regs that you are required to design to limit nuisance or inconvenience and having a rcd trip that is sharing with the boiler circuit could render a dear old lady without heating in winter which borders on the realms of health and safety issues although the regs dont stipulate this senerio its an angle with which you can enforce the issue.
I have issues with boards claiming to be 17th edition compliant but dont afford rcbo ways for this very reason... i would also consider fridge/freezer and alarm circuits to be afforded independent rcbo protection.

 

[Rauer]

Personally in my house I have surface run ( in the airing cupboard ) a seperate ring , for, alarm, central heating, and CCTV , and that also runs up into the loft for a couple of sockets and feeds the loft lights so I can work on the upstairs lighting with the loft lights still on! It annoys me when people run the loft light on the upstairs lights!!

 

[imago]

There isn't half a lot of Henny-Penny nonsense about separating circuits. 'Every appliance and light must have it's own dedicated supply or civilisation will come to an end!'

Cobblers!

Sure it's desirable to separate some, but it's not essential and when people talk about enforcing the issue, or convincing customers that it's the only way it should be done it's just scaremongering at best.

What happens if the gas goes off? What happens if the boiler fails? What happens if there's a blockage? What happens if the circuit trips? The same thing in all cases, someone fixes it.

 

[Darkwood]

Its not all scaremongering imago, agree alarms, fridge/freezer etc all will just be inconvenience at the most if lost but with regards to the heating system i would consider it poor design if it shares the same rcd as several circuits, yes crap happens and it gets sorted but i can walk out of any installation i design in the knowledge that any intermittent or permanent fault not related to the heating isnt going lose my customers heating or hot water at a cost of 25 extra quid for a rcbo, if i was a house-owner and lost the all heating and hot water after a rewire and was told the fault was unrelated then i would have doubts about the electrician in hand (from a customers view), each of my jobs is assessed on site and if the house has alternative methods like gas fires then i relax my views on the heating been dedicated rcbo.

I quoted to wire a block of flats for the council and wasn't the cheapest quote by any means but because i designed the electrics for minimum inconvenience to the customer and reduced urgency on out of hour call-outs for the council i won the contract, they have alot of problems from 17th edition boards losing tenants power over half the board as well as heating and hot-water a senerio which creates many a hostile and angry tenent.

 

[imago]

I absolutely understand and agree that a house should have RCBOs for all circuits as a best case/practise. However, to suggest that a boiler is a special case and should/must be on an RCBO is overkill IMHO.

If a household is so dependant on the boiler that they will be severely affected without it then back up power and gas supplies should be required.

 

[telectrix]

it's not as if the customer is too poor to afford an overcoat. my parents never had central heating. they survived without it for 79 years.

 

[i=p/u]

as long as heating has double pole isolation if taped off somewhere or on its own mcb... i see no problems..
fully loaded cu change for £90 materials or rcbo's at i think £32 each .... every job is slightly different different
what price are hager rcbo's from your local wholesalers.......... just asking

- - - Updated - - -

is why you were the hairy guy at school, growing a coat

it's not as if the customer is too poor to afford an overcoat. my parents never had central heating. they survived without it for 79 years.

 

[Darkwood]

Im more used to larger projects where they are centrally managed by a callout team like Granges for the elderly or even Landlords with several houses, such a design aspect may be considered overkill for domestic but i still argue it gives good design re' heating and worth the discussion up front with the customer, i personally do it on all houses if rewired, i dont push it down customers throats but will recommend it to those without say alternative methods to heat there house, i give a one to one personal explaination of the pro's and cons of putting Freezers, alarms and heating on rcbo's and since the the introduction of the 17th ive never had a customer decline the extra £100 on a house rewires which usually are in the £1500 plus. I dont advertise and all my business is word of mouth, its kept me busy while many around me struggle and i find you dont have to be the cheapest even in these times so it works for me.
Im from a small town where everyone knows everyone and the number of times like most on the forum i suspect gets collared in a pub ''your an Electrician arn't yer mate!!"... over the years its become clear to me that people dont like llosing there heating and hot water because they cant reset the rcd and their views of the companies who fitted the boards goes downhill regardless of whether the installation complies or not.
My opinions maybe a little bit stronger than most but i see my customers in the local all the time so its in my interest that they dont have any reason to complain, a faults a fault and yes they happen but the knock on effects a fault creates in my opinion should be limited in design.
Its in the Regs with regards to keeping inconvenience and disruption to a minimum in the event of a fault so nothing ive expressed is really overkill.

 

[Guitarist]

Just to put things into perspective. Over the last 10 years in this house....

Times I have lost my central heating due to RCD tripping = 0
Times I have lost my central heating due to a power cut = 30+

Yep, I live in rural Norfolk, and we STILL get several power cuts each and every year. The last one was just last week and it lasted for over 4 hours. The whole Village went down, and nobody knows why.

That said, I still personally recommend full RCBO boards. Every little helps

 

[Darkwood]

We all have our preferences etc and im happy to agree to disagree, my set-up and experience gives me my views and domestic isnt really a regular thing so i'll probably carry a strong opinion over from what im used to designing where disruption to other circuits can create even bigger problems than the initial issue, but dont get me wrong im not slamming anyone elses views here... if it complies then its not an issue its just individual preferences

 

[Guitarist]

We all have our preferences etc and im happy to agree to disagree, my set-up and experience gives me my views and domestic isnt really a regular thing so i'll probably carry a strong opinion over from what im used to designing where disruption to other circuits can create even bigger problems than the initial issue, but dont get me wrong im not slamming anyone elses views here... if it complies then its not an issue its just individual preferences

I'm completely agreeing with you here mate. My point was really, that in the real world, however hard we try to "design" a great system, it only takes the local supply to scupper all our valiant efforts.

 

[Darkwood]

When i eventually invent my perpetual motion device to give me free energy then il share the secret Guitarist and i can eventually unplug my house of the street lamp think they are starting to smell a rat ...or my sock i put over the dusk/dawn sensor.

 

[Rauer]

When i eventually invent my perpetual motion device to give me free energy then il share the secret Guitarist and i can eventually unplug my house of the street lamp think they are starting to smell a rat ...or my sock i put over the dusk/dawn sensor.

Just get yourself a lamppost key and tap into the cut out

 

[imago]

I'm not disagreeing with what you say darkwood, I would fit boards full RCBOs for preference. It's just the emphasis I don't agree with, IMHO it's preferrable rather than required.

As for the Regs, minimising disruption is another wishy washy statement IMHO. If it's a requirement then RCBOs should be required and not split RCD boards, which would end the dissagreement and clarify the position.