single or 3 phase for house in the countyside

[lynnandrob]

hi guy's

im new to all this,and would appreciate any help.i have just bought a house in the countryside and the power company need to know how much electric i will be using so they can work out if i will need single or 3 phase connection.
the house is in the sticks so the connection will be suppling the house and a 8 birth static caravan for guest's and family.everything will be run on electicity exept a fire in the van
i have worked out all the lights,cookers,water heating and every thing else electical and it comes to 100kva if everything was on at the same time,this includes showers,washing machine,dryer,electic heaters and cookers ect ect,but how do i work out my consumption ???????????.
here is a list of the main things it will be suppling.

16 x lights (10 in the house 6 in the van)
2 kettles (1 in each)
2 x microwave
2 toasters(1 in each)
2 showers (1 in each)
heaters x 12 (8 in the house 4 in the van)
2 x cookers
1 x water heater
2x washer
1 x drier
2 x fridge
2 x irons
then there are tv's/dvd's/pc's/hair driers ect,ect.
i know most of these wont be on at the same time such as the heaters and washer/drier but if the house and van are full in the cold months the heaters will need a lot of juice.

thanks rob

 

[ezzzekiel]

roughly around 140a per phase but you are going about it the wrong way and probably will need to leave the design to your spark.

A BASIC GUIDE:

we dont break things down by kettles and toasters etc, design your circuits as standard, rings, radials, fixed load appliances etc then apply diversity where possible a quick guide method (i tend only to use on existing installations for quickness) total up your required mcb's take the largest rating and then add 40% of the remainder for your maximun demand to the property if your then hitting well over the 100a range request a 3 phase supply but they will require how many amps per phase to know what size there supply cables need to be.

a seperate sub main on a tt system would be best option for caravan

 

[malcolmsanford]

hi guy's

im new to all this,and would appreciate any help.i have just bought a house in the countryside and the power company need to know how much electric i will be using so they can work out if i will need single or 3 phase connection.
the house is in the sticks so the connection will be suppling the house and a 8 birth static caravan for guest's and family.everything will be run on electicity exept a fire in the van
i have worked out all the lights,cookers,water heating and every thing else electical and it comes to 100kva if everything was on at the same time,this includes showers,washing machine,dryer,electic heaters and cookers ect ect,but how do i work out my consumption ???????????.
here is a list of the main things it will be suppling.

16 x lights (10 in the house 6 in the van)
2 kettles (1 in each)
2 x microwave
2 toasters(1 in each)
2 showers (1 in each)
heaters x 12 (8 in the house 4 in the van)
2 x cookers
1 x water heater
2x washer
1 x drier
2 x fridge
2 x irons
then there are tv's/dvd's/pc's/hair driers ect,ect.
i know most of these wont be on at the same time such as the heaters and washer/drier but if the house and van are full in the cold months the heaters will need a lot of juice.

thanks rob

Problem with trying to sort this out is loads. So lets go this way, forget for now the caravan hook up as there are many things that need to be worked out here, and the biggest by the looks of things are your heating requirements.

The house 10 lights in the house would more than like be split into upstairs/downstairs, but often today it can be split half/half, which is half up/down and the other half up/down but 2 x 6amps circuits.

The kitchen equipment in the house could either be done on radials or a ring final. Personally I would do radials for a kitchen but lets go the route of upstairs/ downstairs/kitchen rings 3 rings in total for all the plug in equipment

The 2 cookers is that 1 in house/1 in caravan or 2 in house, I'll spec for the house and would go 2x 32amp for argument sake.

1 shower in the house we will say 40amp

1 immersion heater ( water boiler????) 16amp

The heaters are the anomaly here as most homes are heated CH, I assume you will not have gas/LPG/Oil boiler. If that is the case then you will need to go on economy 7 night storage heaters, as you would really want to utilise this cheaper heating. that would be 8 x 16amp for 3 kw heaters.

For me it would be

2 x lights @ 6amp each
3 x rings @ 32 amp each
2 x cookers @ 32amps each
1 x shower @ 40amp
1 x immersion 16
1 x caravan hook up ??????? but I would say 45amps.

Total 273 amps and I would times that by 0.4 to give you a diversity of 109amps, and so I would ask the DNO for an 100amp single phase supply. Of course this is a very rough guide using approx figures, you may have bigger cookers or larger showers than I guesstimated, but it is a guide for you.

As you will hopefully utilise night storage heaters, chances are you are not going to be showering, cooking at midnight, and so the 100amp supply for night storage heaters should be ok. Again though this in conjecture on my part, and the only real way to design is is to know your exact requirements.

The caravan hook up I guessed at 45amps. Again not knowing the frequency of occupancy and how you are going to utilise another 4 heaters, which is quite a lot for a caravan, that 45amps can easily be underestimated or over estimated by me.

Your biggest problem here is the caravan hook up, a lot will depend if the DNO supply you with what is called a TNC-S system. A caravan hook up comes with a lot of stipulations, and that TNC-S adds even more.

My advice is to get a local electrician in to give you advice, I'm sure if you posted your location here, you may have one of the lads off here contact you to give you advice and quote a price for you, because in reality your going to need a lot of expert advice on this project

 

[lynnandrob]

hi and thanks for the replies,

regarding the van supply,i was trying to work out the very max load it would use,if you could just imagine this

its winter and very cold,all the family have been to the coast which is 5 min's away,everyone is freezing so
the first thing they will do is turn turn all the lights on,the heating goe on,the cooker and kettle go on for a bit of supper and the kids/grandkids get in the shower before getting ready for bed the tv will be on,so in minutes the power has gone from 0 to approx 5kw.then there is the little exras leccy blankets/hair driers ect.
the same thing will be happening in the house on with more heaters.
and that is how i was working out the very max load.

thanks once again

p.s can you tell me how many kw/kva you can have on a single phase

 

[pblec]

i will have obviously missed something and look forward to it being pointed out.

who is paying for it, has it not already got a supply (i will not go into if their is 3 phase outside on a pole - thats beyond what i should coment on), if you fit single phase and later on find you need 3 phase who will pay for that.

even if you manage to design and get it to needing single phase how upgradeable is it.

for me its 100A per phase with each phase only being used as single phase, so 100A into house, 100A to caravan hook ups, leaving a 3rd phase for whatever storage heaters or spare.

its the costing issue really the 3 phase is better as its future proof, but some of the guys which have all the supply experience will tell you better.

 

[JD6400]

I am with Pblec on this one , if there is not a massive uplift in cost always go 3 phase where possible , you never know what the future may hold !

 

[IQ Electrical]

I don't design by crystal ball but I think maybe allowing 100A for a static caravan might be rather generous?

Then you have the heating load, just taking the house at 8 X 3.4kW night stores, you're looking at 118 Amps until thermostats start to diversify the load (quite a while with night stores).

If the 3-phase installation cost is as high as it often is 'in the sticks' then I'd be looking at oil or a Calor tank for the house heating.

 

[lynnandrob]

hi guys

the house is in the sticks with power poles going over the fields,the house has never had a power supply and has not been lived in for over 50years,there is a pole nearby where the supply will be coming from.when i first contacted the the supplier (western power)i asked for 3phase as i knew that would cope with everthing i could possibly need and that was when they asked what the load was going to be.it will be me who has to pay for the connection (possiby 15k) so i dont want single if i then have to upgrade to 3phase.im not too keen on the gasoil or bottled gas as there is a lot of pilfering in the sticks and i dont want to pay for stuff to be nicked by the pikies who are always knocking about.thats why i want everything electric,i will probably have a woodburner in the livingroom but that wont take much of the consumption rate.
how many kva can you put throu a single phase????

thanks again

 

[pblec]

sorry did not mean to imply 100A for caravan meant to imply seperate phase supply for the caravan to reduce the potential loading in the house.

i think you knew that deep down but thank you for pointing it out i should've been more specific

i just generaly work on in the domestic front the max i have is 100A per phase.

 

[Deleted member 26818]

The amount you can have through single phase is limited to the size of the supply cable.
In my area, single phase is in general limited to 125A, and 3phase is limited to 200A per phase.

 

[malcolmsanford]

i will have obviously missed something and look forward to it being pointed out.

who is paying for it, has it not already got a supply (i will not go into if their is 3 phase outside on a pole - thats beyond what i should coment on), if you fit single phase and later on find you need 3 phase who will pay for that.

even if you manage to design and get it to needing single phase how upgradeable is it.

for me its 100A per phase with each phase only being used as single phase, so 100A into house, 100A to caravan hook ups, leaving a 3rd phase for whatever storage heaters or spare.

its the costing issue really the 3 phase is better as its future proof, but some of the guys which have all the supply experience will tell you better.

Not sure I would want to leave a phase spare, with the other 2 loaded.

I'm also not sure you will be needing 3 phase 100amp per phase either. I'm also reluctant in a domestic situation of have 400 volts.

As I said and IQ it is virtually impossible to design a system like this. I have ever to see a caravan with a 100amp supply. Where i live in Kent there are many of these residential sites, that have the 3 bedroom chalet type homes, with electric central heating, kitchens on suites etc etc and I have yet to see them exceed a 60 amp protection device and often just a 40amp.

The OP as suggested a wood burner/solid fuel, these can often be utilised with back boilers, which will give you heating and hot water. Night storage heaters are not my cup of tea and so there are alternatives.

 

[pblec]

sorry guys this will be my last post on here as its down to the 'big boys' i too live in the middle of no-where (lincolnshire) and i know i've been into several remote houses where they have a 3 phase supply but only use it as 3 single phase supplies several have 1 cut out not connected to a meter so are spare, i've never yet found a new supply with anything smaller than 100A, and may be wrongly beleiving thats the max they can supply (its not my job to know that)

i purely check the supply to see what the cut out is rated at then design the install - if its not up to spec get the DNO to sort it out, i tried this once and they said they won't up grade until it blows (telling me to unofficialy overload it) so 40A fuse 14 kettles, 10.5 kW shower all the lights on oven on throw the main switch absolutly nothing it all worked customer said he'd get more kettles whats the point it handled that load, i just put it as a coment on the instal cert.

 

[IQ Electrical]

sorry guys this will be my last post on here as its down to the 'big boys' i too live in the middle of no-where (lincolnshire) and i know i've been into several remote houses where they have a 3 phase supply but only use it as 3 single phase supplies several have 1 cut out not connected to a meter so are spare, i've never yet found a new supply with anything smaller than 100A, and may be wrongly beleiving thats the max they can supply (its not my job to know that)

i purely check the supply to see what the cut out is rated at then design the install - if its not up to spec get the DNO to sort it out, i tried this once and they said they won't up grade until it blows (telling me to unofficialy overload it) so 40A fuse 14 kettles, 10.5 kW shower all the lights on oven on throw the main switch absolutly nothing it all worked customer said he'd get more kettles whats the point it handled that load, i just put it as a coment on the instal cert.

Lol, tell me this is a wind up?

And why your last post? It's all just good discussion

 

[pblec]

no not a wind up at all that happened in market harborough. my problem was mid terrace victorian 2 up 2 down extension to rear for kitchen i couldn't find supply characteristics 2 wires coming through party wall inta a meter and an MET, neighbour had fell out due to the work so wouldn't allow me access to visualy confirm, phone DNO to ask all they can say is if it had been PME'd in last 5 years, great test it but that will just give me a Ze which could be good or bad, customer had DNO coing out to see about putting external meter in so i made sure i was present for his visit and thats how i got the un-official reply, he also demanded access at the neighbour for me to confirm TN S, but you all knew that from my property description. always puzzles me why i fit 25mm tails to a meter fed in 16mm or less.

the only reason for the last post bit is purely i can't add anything else other than what i posted and as a domestic only bloke thats what i would've done.

i've only replied as you asked if i had seriously done that.

 

[ezzzekiel]

without being rude your plan to leave is probably the best, you appear out of your depth with the design side, maybe get someone in for the initial design work then you do the install as its only domestic you should be within your comfort zone.

 

[lynnandrob]

hi guys

i think i might just be getting the hang of this now.(i hope this is right)just for the van i would need

1 x 32amp for the sockets (possibly 7 double sockets)
1 x 6amp for the lights (6/7 lights)
1 x 40amp for the shower
1 x 32amp for the cooker
1 x 16amp for the water heater
1 x 64amp for the heaters ( or 2 x 32amp)
making a total of 6 fuses in the fusebox and a total of 180amp for the van

the house would be
2 x 6amp for the lights (6amp upstairs 6amp downstairs)
2 x 32amp for the sockets (1 up 1 down)
1 x 40amp for the shower
1 x 32amp for the cooker
1 x 16amp for the water heater
then there are the 8 heaters 4 x 32amp
making a total of 292amp for the house =472amp for both
is that how you guys work it out??.

we may get a back boiler for the fire but would still have the heaters because of the speed of heating the house and water.

 

[malcolmsanford]

No Lynnandrob that is not how you work it out sorry. In my post 2 I tried to explain diversity to you a little. I really think it is time you bit the bullet and asked for professional help in this.

Not being funny if you had a real medical condition would you keep on the NHS health line right this is it now what is wrong, is it this, they would advise you to go to a doctor. I'm really advising you contact an electrician or as I said post your location and perhaps one of the lads here can help you.

 

[pblec]

red rag to a bull this, please justify your comments and bear in mind we are a technical forum so so 'because its always done that way doesn't wash'

i designed an instalation correctly i actualy used diversity and worked out potential loading purely because it was so close to when i did my course (how many of you use rule of thumb). i worked out that the supply could not cope with the demand so approached the supplier to do this before any work had taken place and followed the suppliers advice.

i did read your reply and yes thats how i now work out demand as applying diversity is irrelevant i. regardless of your opinion on domestic installers we are qualified to design and yes i posted up here the process i went through to highlight a problem i had found.

i am in my comfort zone for designing domestic, and could you please clarify if me allocating 1 phase for the house, 1 phase for the caravan and the 3rd phase being for storage heaters / spare is unsafe or may possibly be over cautious using the information provided.

yes its a discusion IQ invited me to reply, why the flames?

 

[malcolmsanford]

I'm not sure who your aiming for pblec but I assume I'm getting some of the fire, If you had a 3 phase supply and loaded the house, the caravan on a phase each, and then left last phase for the night storage heaters/spare then you are unbalancing the load, as the heaters will only work at night.

 

[pblec]

MS not at all sorry the reply button doesnt put the reply under the post its intended i'm aiming this at ezz.

but then his reply may not be aimed at me - i think it is though

as for the loading your probably bang on the other reason for the way i designed this is potential cross phase problems within the property / instalation, may be slightly over cautious but would make the install and future testing easy.

 

[IQ Electrical]

I think this highlights the problems with what I call 'crystal ball design'.

We all have our own ways of working and applying diversity, the competent electrician standing in the property, looking at the room sizes and armed with a DNO quotation for 1 and 3 phase supplies for that property will no doubt arrive at the best solution.

 

[ezzzekiel]

its intended i'm aiming this at ezz.

cant see how my reply could possibly cause offence as after offering advice you were obviously still struggling with the design, all i said was get someone to help you with the design stage then carry out the works yourself.

but as it stands you keep counting kettles and toasters and ill move along

 

[lynnandrob]

i think things have gone a bit astray here,im the one needing info on single/3phase consumption.but pblec and ezzze have got there wires crossed with who's who's.ill probaby get a sparky to work out the load and just hope it will be single phase.or get a seperate feed to the van.
thanks for all the input but im still none the wiser to how much the load will be.

 

[ezzzekiel]

work out what circuits you require,
example: 2x ring circuits at 32a + 2x lighting circuits at 6a etc etc
take the largest rated which is one of the 32a then add 40% of remainder so 32+6+6 x 0.40 = 17a + the original 32 = a demand of 49a. if after doing this simplified calc your over 100a then request 3 phase (you can calculate the amps needed per phase when you have the total)

after that its basic domestic wiring which i assume your confident with.

 

[pblec]

if your the householder then you'll obviuosly have your own electrician to design this install and provide your own advice. or find an architect to do the design draw up a plan then invite tenders. once you've got all of this then sort out your supply.

EZ gave you fantastic advice in his 1st post as the remainder have done the same all with differing perspectives, the main constant is you need to get a profesional in to specify this install and with your input designing this you will end up with the house you need. if you hadn't worked out yet its not a job that can be specified over the internet on a forum as we have so many variables and what ifs.