Chasing out depth for cables for rewire

[tonyelectric]

Possibly just stunned silence that you use polystyrene with cables?[/quot
not over 100mm in depth are the cables passing through...

I don't think riveralt was talking about the depth of the polystyrene, more about the fact that polystyrene reacts very badly with PVC by absorbing its plasticisers

 

[ElectricianDirect]

Possibly just stunned silence that you use polystyrene with cables?[/quot
not over 100mm in depth are the cables passing through...

I don't think riveralt was talking about the depth of the polystyrene, more about the fact that polystyrene reacts very badly with PVC by absorbing its plasticisers

Please note this point made by TonyElectric. Where polystyrene is used to prevent plaster entering the cavity made behind skirting boards it should only be used to wedge capping back and not contact with the cable.

Where cables enter a loft space through 100+ mm insulation material trunking should be considered to ensure cables load properties are not reduced due to the insulation material.

Where stud walls contain 100mm insulation cable sizes used should be increased for the whole of the circuit, hence a 2.5mm T& E cable should be increased to 4mm T&E. On traditionally constructed homes stud walls are sometimes utilised in extensions and/or area divisions, i.e. en-suite shower.

It is very important to ensure electric shower cable is not run through insulation - this cable is probably the only cable that may be used near its full load potential.

Thank you to TonyElectric.

 

[ElectricianDirect]

I'm going to get my house rewired but want to save some money on the electrician so will chase out the boxes and cable runs myself.

For a full rewire (so Part P notifiable) how deep and wide do I need to chase for the cable into a brick wall? Can I just remove the plaster and go back to the brick?

The minimum possible cuts and chases is the best answer! Building Reg's has a section regarding 'Structural' and I have seen too many cut well over halfway into a brick (or even knock a brick into a cavity) thereby reducing the load bearing capacity of the wall... Now imagine 3 double socket outlets, an aerial outlet and a telephone outlet grouped together and the cutting/chasing undertaken by an "house-basher" (as opposed to a person minimising disturbance...).

Chases... I use capping to mark out chasing required. This way the width is sufficient without being excessive. It's good practice to chase below the tops of skirting boards with the view to enabling cables to be removed from the back box to alter the circuit later... Maybe an additional socket will be required later.

Chasing machines... I utilise a dust extractor when using chasing machines and dust still seems to go everywhere? In an occupied home "by hand" with a large bolster saves an equal amount of time (if not a lot more) in cleaning!

With traditionally constructed homes I do not use the old cable routes - I prefer to ensure I can get under the floor boards (sometimes making an "hatch" in the under stairs cupboard) and plan from here... Chasing walls to get the cables upstairs is also very messy and not user-friendly when future maintenance is to be considered. My normal approach is to widen the chimney breast by a couple of inches with a frame and plasterboard. The cavity provided enables a length of trunking to be run up the inside into the upstairs floor void. The same plasterboard void may also be utilised for a double socket outlet or other accessories and provides a excellent route for co-ax cables, telephone cables, alarm cables and data cables WITHOUT HAVING TO CHASE OR CUT OUT BRICK WALLS!!!!

The way the floor boards run upstairs contributes a lot to positioning of sockets and other accessories. I want to lift a floor board at either side of the room only, but I am a specialist! If socket outlets or other accessories are required along the 2 walls where the floor boards haven't been lifted, then I cut circular access holes through the floor boards (and batten underneath) to provide points at which cables can be accessed. There is normally a flooring support joist just off the wall at this point and so a notch is required to insert cable(s) through - I would normally clear the area behind the skirting board at this point to "fish" the cable up and fill with polystyrene or similar prior to making good. Maintenance, maintenance, maintenance...

With a floor board up at either side of the room either a pendant light or down lights may be installed. For Pendant lights I cut out a 3" hole to use a dry-ling box to mount the pendant on - this also facilitates feeding cables through the ceiling void to the edge where the floor board has been lifted.

A room-by-room approach minimises disruption and disturbance to decor.

Room lighting switches, where possible, are mounted back-to-back, so just one chase is required to cable both rooms lights. The ring main circuit, where possible, exits one room and enters the adjacent room back-to-back. Where bathroom floors are concerned, any electrics beneath I install from the adjacent room - this saves having to remove tiled floors for access later

Where possible, I would also run the trunking from the first floor void up into the loft space either up the inside of a cupboard or using the bit on the side of a chimney breast approach.

Electrician's hourly self-employed rates are between £20 - 25. For those who choose to liaise closely with the builders' work aspects of a home's electrical installation refurbishment the savings not only in time and money, but in heartache and misery, can be most advantageous.

I have undertaken works on the above basis from the North of England to the South of England and what I appreciate most about such is home-owners and/or others assisting obtain a knowledge of home electrics - even the testing procedure to verify the safety of each circuit - which, at the least, enables the determination of the many Indians whom the Cowboys disguise themselves within.

Apart from Part P of the Building Regulations, there are also other Parts to consider including energy efficiency, fire safety, access...

A good electrician will meet the needs of a customer... I find arriving on a Wednesday/Thursday enables the customer to take a Friday off of work and assist with the electrical refurbishment of their home on the Saturday/Sunday too.




For those who require further information please send a message directly

I've just got online again after the weekend - but thank you ever so much for your post. It's both very informative giving me some ideas for when I tart to chase out and I'd certainly agree with you about it being useful to have some knowledge of the wok (any tradesman does to be able to identify the cowboys. It also makes a lot of sense for those of us who are on modes incomes to do some of the basic work ourselves and save paying a highly skilled professional having to knock out bits of plaster etc.

Thanks again for what I'm sure will be a useful post or a lot of people!!!

The essential tool for home rewires would be an angle attachment for your drill. This enables holes to be cut through joist professionally... On a listed building I had observed previous works included cutting holes through joist at a angle - commencing in the middle on one side and exiting near the bottom on the other side of the joist. This weakens the load bearing capacity of joist. As a guide I would recommend 1/12 the depth of a joist for maximum hole diameter and the holes to be spaced 2 x the diameter of hole apart.

All TV co-ax/alarm cables/data cables/telephone cables should be 300 mm away from mains cables, but where such is unavoidable simply run these cables in flexible PVC conduit to provide a contained route ensuring, under fault conditions, 230+ volts will not liven up such cables.

The life span of an electrical rewire is 20 years plus. The cost of a rewire should be considered in terms of pence per day over a period of 10 years. On this basis to add a switch beside your bed to turn off/on the main bedroom light or to add a circuit in the living room dedicated to table and corner lamps is very cost-effective in time saved over the next 10 years.

With 4 table/corner lamps in a living room it takes just minutes to turn them all off or on (sometimes having to use awkward lamp switches). A few minutes a day, 7 days per week, 365 days a year... It is so simple to have a 3-gang light switch at the entrance to the living room for general lighting, accent lighting and task lighting. No more wasted minutes.

Lighting circuits. It is normal practice to run an upstairs circuit and downstairs circuit. I would advise an additional circuit for entrance/upstairs landing/bathroom and outside lights on an RCBO. Why? On the basis one circuit trips, light overspill from opening doors provides at least a glimmer of light where none would otherwise be.

Above the consumer unit consideration may also be provided to adding an emergency light unit - this is a good starting point for the lighting circuit that illuminates within the region of the EMU and if, for any reason, this lighting circuit "trips", then the EMU comes on and you're not in the dark around your C.U.

Fridge/Freezers may be put on a non-rcd protected radial circuit if the cables are either 50mm deep in the walls or surface mounted - I prefer the latter , but routed through mini-trunking behind the kitchen units and protected by a fused spur (a switched fused spur may be turned off by accident!). This way, if you are on holiday and the motor starting up/earth leakage may lead to tripping an RCD protected circuit, on your return you may discover hundreds of pounds worth of defrosted produce.

Consumer unit selection... I prefer CU's with 3 banks - 2 banks for RCD protected circuits and the third for simple MCB's including the smoke alarm system cabled in FP200.

I understand "modest income". Since I have had children it would seem I have never had the luxury of "disposable income". My partner has returned to full-time study, hence Monday's & Tuesday's I have caring duties "just in case". I no longer advertise for away work on my website (even though one of my on-going projects is on behalf of an ward-winning British designer and architect in Central London and another is a 300 year old listed farmhouse in the wilds of Cumbria), but working away is the solution to meeting family needs and remaining a self-employed person when it's a tough economic climate for most.

Altruism - it's nice to be nice - and DIYnot is good for all.

 

[martinxxxxxx]

Hi Richard

Thank you for your insights on how t rewire a house. I always find it interesting to hear new and novel approaches to the job.

I did not understand what you wrote in this bit though, would you mind explaining it to me a bit more please

"Electrician's hourly self-employed rates are between £20 - 25. For those who choose to liaise closely with the builders' work aspects of a home's electrical installation refurbishment the savings not only in time and money, but in heartache and misery, can be most advantageous. "

Are you saying you are charging a much lower rate than this?

Thanks

Martin

 

[ElectricianDirect]

Are you saying you are charging a much lower rate than this?

Martin... During the Summer I drove down to the Kent Coast to undertake a designed electrical installation refurbishment. A journey of 300 miles! A day to get there and a day to get back at half my normal hourly rate. I pitched a small tent on a beautiful camp site overlooking the English Channel to reduce lodging cost whilst working away. When I undertake price work the x-factor must be a part of such to take into account unforeseen issues, hence prices may appear high as a consequence so I always provide an hourly alternative.

Some of my customers accept the unforeseen issues as part and parcel of electrical works and prefer to pay an hourly rate comparable with what employment agencies seek for the provision of electricians (quality maybe unknown) to electrical contractors. Other advantages of employing an electrician directly (hence why I market my services as "Electrician Direct") are alterations to the proposed design do not incur the cost of "extra's" (sometimes disproportionate to the actual works).

The home-owner or even property developer may even choose to work alongside me to reduce the hours required to complete jobs.

The question is what do I charge hourly... As low as £17.50 per hour based on 9 hours per day and paid at the conclusion of first fix/week or 2nd fix/week

PS I've worked for a national company at double this rate, but the company were very slow payers and my rate was raised to take account of such. The company are also ruthless in business and I prefer to work with a bit of give-and-take and establishing good customer relationships.

I consider electrical works to be health & safety orientated, hence an hourly rate provides no excuse for short cuts as a consequence of wanting to get home early to watch a football match or a boss constantly rushing you to get the job done due to wanting to increase their profit from the job to the max and used towards the purchase of yet another property to rent out to British holiday makers in the USA...

Have a look at the reference on my web site regarding flood works in Carlisle... This is what a customer receives for £17.50 per hour

 

[tonyelectric]

Blimey ElectricianDirect you are cheap, round here £35 is the going rate, many contractors here charge £45 an hour (and we are not talking call out fees, thats hourly!!). I have to pay my unqualified manual laborer £20 an hour, though saying that he works bloomin hard (he's currently laying a 35mm2 4 core SWA across a school field in the snow ).

 

[ban-all-sheds]

he's currently laying a 35mm2 4 core SWA across a school field

Didn't you tell him to bury it??

 

[tonyelectric]

Ha, yep he's burying it I hope and with luck he's remembered to lay the warning bricks above it too

 

[martinxxxxxx]

he's currently laying a 35mm2 4 core SWA across a school field

Didn't you tell him to bury it??

Richard Why so low

£17.50 an hour! By the time you pay tax, insurance, van running, downtime and all the rest of it I think you need to arrest yourself for paying yourself below the minimum pay rate. I charge the going rate above and I still don't have any disposable income then I do have two litttlens too. There is no reason you should work for so little.

I also have worked for a national co, I agree with your sentiments about them. Probably the same company but I am not able to say.

 

[ColJack]

I feel I must comment on your first fix comments

If you fix sockets back to back, you are limiting the posibility of moving that socket.
You are also then removing more than half of the wall thickness for a standard single brick internal wall ( assuming you use 35mm backboxes since you can't know if the homeowner will want to change to flat plate accessories at some point. )
There's also the point that by removing over half of the wall where 2 sockets are back to back, you reduce the availible thickness for getting a fixing screw to hold, not to mention the possibility that if you're accurate then the screws from either side will foul each other..

You say you widen the chimney breast? that then makes it uneven on one side and affects the aesthetics of the room not to mention any affecting any pre-owned shelfing / cupboards that may have been purchased for that niche..

 

[martinxxxxxx]

I wanted to hear more from Richard before delving into the detail. But as his other posting has said he is leaving the forum till after the new year.

It did strike me that most home owners I have met don't want the electrician to start putting up box partitions as they normally have some one else in doing the plastering and decorating with whom they are discussing the end result of their decor. Discussions that I neither have inclination or invitation to be involved in.

I was really interested to hear more though especially about the method of hatches and holes in the floor and ceiling to put the wires in. More detail please.

I like to do offset back to back sockets for the reasons you give plus a lot of the time the offset allows you to align the next sockets with the run of the joist in the next room so that you can come straight down without hitting the joist.

But there are many ways to skin a cat and you are right to take time to point out to the unwary browser of this thread that Richards posting is not a definitive guide to wiring, and in fact it is a bit out there compared with normal practice. A DIYer trying to get this past a particularly pernicious BCO might have to justify some of the decisions made and by using the advice above may without Richards in depth knowledge struggle to convince the official why they have not gone with the norms of rewiring.

Thanks ColJack

Martin

 

[ElectricianDirect]

When an old school tradesman turns up at your door I guarantee they have at least a brush and a dust pan. My tool kit includes industrial suction cleaner and a dust extraction machine. "Why?" is because I work within peoples home's.

By "back-to-back" the cable goes from one box to another (in PVC conduit is good practice) without going down and up...

Some of the homes I work on have 3 foot stone walls, but "sod's law" is that the joist on the other side of the wall is in the way of a straight down the wall cable run, hence "back-to-back" through a 3 foot thick wall could actually mean the angle I drill through at is one where the full length of my 5 foot long drill bit is just long enough.

I consider myself an electrical-mechanical installer (after a 20 year span installing goods and passenger lifts or undertaking the major refurbishments thereof in the South of England). When undertaking rewires I may also include automated gates or garage doors, whole home ventilation / heat recovery systems, X10 home automation / security installations, home networks...

10 Years ago I moved to a market town smaller than many council estates and with Hadrian's Wall at the top of the hill. Over the past 10 years I have undertaken industrial, commercial and electrical installation works (references on website for some of such), but in 2005 I was asked to aid a charity and assist resolve Electrical Regulation non-compliance issues on behalf of Flood Victims in Carlisle. 3 Years later I was still doing so and all the negative aspects provided issues which should be addressed prior to undertaking home rewires, especially rewires in occupied homes.

So... I have served my time up lift shafts and not as an electrician, but all you electricians know how much wiring is involved in the installation of lifts as well as the working tolerances of the mechanical aspects over 15 or 20 floors.

Whilst at college doing a BTEC I worked as a kitchen studio rep and then a kitchen designer. The first kitchen I designed for a wheelchair user was designed alongside the customer sitting in his spare 'chair, hence I become familiar with Universal Design concepts...

"House-Bashing" is the name given to house rewires by electricians... A good house rewire electrician must have an understanding of home construction and must be willing to go the extra mile to meet the needs of the customer.

First need: reduce disturbance to decor and disruption to household to the minimum.

Second need: reduce dust pollution and leave work area safe and clean at the end of every work period.

Third need: to trust...

Many good points have been made regarding my post and I welcome them all both negative and positive. Especially the negative. "Why?" Because in resolving the negative such becomes a positive!

Every home is different even though the construction of the home may be identical to others, but peoples NEEDS are different. The essential part of any rewire is ASCERTAINING those needs. If a customer rewires the underfloor area thermally insulated at the same time as the rewire, then a rewire provides a cost-effective time to undertake such. If a customer is considering a loft conversion, then running extra cables up to the loft for sockets, lights and smoke detector as part of the rewire is cost-effective. If a customer simply wants the loft boarded out for storage purposes the rewire provides a cost effective time to do such (and ensure all cables underneath are accessible via running in conduits from 50mm x 100mm trunking run along the eaves area of the loft).

Unlike industrial or commercial electrical installation works the domestic consumer wants a package deal and gone are the days when an electrician can say "I'm not doing that - it's not my job".

"There are many ways to skin a cat" is very appropriate to home rewires. I prefer to say "a rewire is a compromise between what the construction of the home allows and what its users require - the nearer we get to the latter the better the compromise".

On the basis I first fix 6 double sockets, an aerial outlet, a telephone point, a data point and dedicated lamp sockets in a living room in a day, the day is made longer by ensuring such are not knocked out of alignment by an heavy handed plasterer - there's no need when I can mix up a bucket of Bonding and make good around each back box to just below skim plaster level. Then make safe and clean up the work area.

The following day, if the home is occupied, I 2nd fix, by-pass the original sockets in the room where I've been working and remove the existing electrics. The new sockets are tested and run on a 16a protected radial circuit from a new consumer unit and this circuit will eventually become a 32a ring main when, for example, after the adjacent dining room is rewired.

"Yes" it is a lot of mucking about, but this is my Unique Selling Point (as a CEO up in the wilds of Cumbria says) and why customers fit in with my schedule as well as my fitting in with customer's schedules.

The point where shelving is located within an alcove is great - some see such as a problem, but I see such as an opportunity.

Whether your property is large or small, traditional or modern,
lighting is one of the most important yet most frequently
overlooked aspects of home improvements. (This is from my website)

A day's work can transform some dusty, old shelves into a focal point with a bit of imagination and the correct use of lighting to accent such.

Aesthetics and balance is of utmost importance and keeping everything in perspective vital to the overall customer satisfaction. I love it when neighbours pop in for a cup of tea near the end of the job and they say "Woww! Why didn't my electrician tell me about doing that...?".

My response to the above is "I'm not an electrician - I am an electrical-mechanical installer who specialises in home improvements".

Many electrician's poo-poo the room by room approach because, first and foremost, they want to make money as quick as they can. I want to make money, but every job I do leads to another due to "customer satisfaction".

As low as £17.50 per hour also has the travel element added, but still highly competitive with many local rates in the South and North of England. The hourly rate benefits those on modest incomes who cannot afford a complete rewire at a particular moment in time, hence a phased approach is planned. Each full rewire I allow 2 weeks to undertake and, if I complete ahead of schedule, I return home early. If issues become time consuming, I work extra hours to complete on schedule.

An example of a price quotation may be viewed at my website. With some electrician's charging £60 a socket or £60 a light does not fit into my pricing structure as some lights I install may have 3 switches, i.e., at either side of master bed and at entrance to bedroom with an additional switch for a reading light at either side of the bed too.

My partner is now making noises... It is now time to devote time to my own family and no further last post.

There's a difference between "house-bashing" and "home electrical installation refurbishment". If any of you have a NICEIC 17th ToolBox guide you'll see just one image of a person within and, fortunately, it's my back side.

 

[tonyelectric]

Well it certainly sounds like you are a highly competent engineer and very competative and professional with it which can only be commended, its always interesting hearing other peoples takes on the field of electrics, and as a 99% commercial spark it's interesting to read about problems and solutions in the home (householders tend not to want galv trunking round the room with round conduit drops to the fittings, can't think why ) very best to you and look forward to your future posts.

Happy xmas & new year

 

[Wontdothatagain]

householders tend not to want galv trunking round the room with round conduit drops to the fittings, can't think why

I cant either, i ran 2 new socket radials in galv conduit and metal surface box's into our utility room (what i had in the van) and "ere indoors" throw a potted plant at me and demanded that it was removed and done "properly"

 

[ban-all-sheds]

...after a 20 year span installing goods and passenger lifts... X10 home automation...

Things have moved on in 20 years - X10 is slow, unreliable, and limited in scope.