hot tub supply in domestic dwelling 32A, 100A supply

[ian w j]

Help Needed !!
The wife has just purchased a hot tub off eBay! I am a spark but not a bright one!! I was just looking into what's required for the supply and they are stating 8-10kw load 32-40amp supply. To an an isolator and have Rcd protection.. yeah ok so far. I know about the zones regarding position of isolator and other equipment as per the regs, but I am stressing about the demand and diversity of the installation. I'm going to do the work and get a friend to pass it off and certify.

Currently I have a 100amp single phase domestic supply.

The dis board has:
2 x 32a rings
1 x 32a radial cooker supply with single socket(cooker is 13a socket)
3 x 6a radial light
1 x 6a smoke
1 x 6a water(no immersion heater)

I've done a diversity calc not taking into account the smoke and the heating time clock and come up with 103amps using a 32 amp supply to the hot tub.
My supply is 100amps !! Is this right??

 

[Bobster]

Your an electrician, that is going to get someone else to pass it off and certify?

Pull the other one, it's got bells on it!

 

[ian w j]

Thanks for your constructive advice! And it will, as all the work is being done under a building notice with the local Building Control!
Constructive answers please!

 

[Darkwood]

Firstly 100amp is the DNO carrier rating, it may have a lower rated fuse in it.

If your holding the title of Electrician then basic domestic diversity should be well within your knowledge and if you need a reminder check your OSG for a reminder.... If you claim to be an Electrician then state your not too bright then its just a matter of time you put yourself or someones life at risk or property for that matter.... I seriously hope it was a jovial comment and not an admit!

PS Welcome to the forum ... emoticons help a lot when expressing sarcasm, comedy anger etc and saves us misinterpreting your post

 

[Bobster]

No problem.

Ok then. If you show me how you got to that staggeringly wrong diversity calculation. I'll tell you where you've gone wrong and how to get it right.

How's that?

 

[ian w j]

Cooker 10 A plus 30% plus 5amp for socket
32amp full load of hot tub.
Help is much appreciated

 

[ian w j]

SORRY HALFTHE POST MISSING!
What is was supposed to say was :
1st 32amp 100%
2nd 32amp 40%
light 6amp 66 %
light 6 amp 66%
light 6 amp 66%
cooker 10a plus 30% plus 5amp
32amp full load of hot tub

 

[irn-brue]

Move this question to the diy thread.Thats a constructive answer.

 

[ian w j]

Just to confirm I am an Electrician but the knowledge learnt about domestic is all in the back of the grey matter! I have worked for the last 10 years on pumping stations and control panels so dont really get to use diversity and demand of circuits as they are designed and never really changed! They normally have 3 phase star delta controls with a small dis board which supplies 1 light, 1 rcd socket and a small tube heater.
If you are ever stuck with these I may be able to help!!!:stooge_curly:

 

[ian w j]

thanks irn-brue:willy_nilly:

 

[martinh89]

whats your cooker rated at ?

You can diversify diversity, you just need to look at a few things closely, like lighting, is it incandescent or fluorescent ect ....

 

[ian w j]

Its run off a 6mm radial B32 , to a socket outlet 13A/cooker switch to a socket outlet behind the cooker. Could I change this for a B16, as the wall the socket is on is going to be knocked down, so only need a supply for the cooker. Sorry to confuse the matter!irate:

 

[martinh89]

And there is always the fact that whilst your using the hot tub , it is highly unlikely that your cooker and hob will be on whilst all your lights are switched on and all plug sockets in the house will be under load .......

 

[martinh89]

Its run off a 6mm radial B32 , to a socket outlet 13A/cooker switch to a socket outlet behind the cooker. Could I change this for a B16, as the wall the socket is on is going to be knocked down, so only need a supply for the cooker. Sorry to confuse the matter!irate:

That's a different story all together mate, if you want to supply your cooker on an independent circuit of its own youll need you current design current and then choose a protective device with a suitable rated current ect ect ect ....

 

[Guest77]

:smilielol5:103 amps? lol

 

[ian w j]

Yeah get that, just no need for a 6mm 32amp radial running a 13amp single socket.

 

[trev]

1 x 6a smoke

I'm putting in some Aico smokes tomorrow, Ei 141. 40 milliamps each. so there's a saving for you straight away.

 

[martinh89]

Its run off a 6mm radial B32 , to a socket outlet 13A/cooker switch to a socket outlet behind the cooker. Could I change this for a B16, as the wall the socket is on is going to be knocked down, so only need a supply for the cooker. Sorry to confuse the matter!irate:

So what your saying is your cooker isn't on its own circuit but on a radial socket circuit ?

 

[ian w j]

Confusing myself now! It's on its own circuit, it is a radial, to a cooker control unit which incorporates a single socket. The feed from the cooker control goes behind the cooker into a 13amp socket outlet not a cooker connec tion point. (the cooker is on a plug top, as per when it was built in 2002. Hope this is a bit clearer!

 

[ian w j]

Thanks for that, it may help! Plus all the energy efficient lighting in the house, considering they were designed with 100watt per lamp holder.

 

[DPG]

Its run off a 6mm radial B32 , to a socket outlet 13A/cooker switch to a socket outlet behind the cooker. Could I change this for a B16, as the wall the socket is on is going to be knocked down, so only need a supply for the cooker. Sorry to confuse the matter!irate:

Dropping MCB size will not reduce the current drawn! Daz

 

[ian w j]

No but if you remove the fit a cooker control unit with out a socket you are limiting it to 13amp!

 

[ian w j]

Think we are going off the subject in hand now though! Can anyone give me a true estimate from experience what the current load is likely to be using diversity for the installation? I've seen a post saying a good rule is take the largest breaker and add 40% for the total if the remaining! This gives me about 90 amps

 

[Andy78]

Have you found out what size DNO fuse you have yet ?

 

[trev]

Ian, apart from anything else it's your house! You know the usage patterns on this one mate. That's more use than anything you'll get out the OSG.

 

[dazza1981]

Dear god help me !!!!
This is year 1 college stuff and amature at best. Seriously mate i dont want to have a dig here but you should be able to figure this stuff out naturally if your a sparks ????
Let your "mate" who is going to sign it off do the whole install if he is any good and get it done properly!!!!

 

[ian w j]

It's a 100 amp, type 2 b 1361 without cutting off the seals, that's what it says on the tin!irate:

 

[trev]

What it says on the tin isn't necessarily what's inside it mate.

 

[Guest77]

It's a 100 amp, type 2 b 1361 without cutting off the seals, that's what it says on the tin!irate:

now look fella pull yourself together, if you look at what you have posted again you will see you have the same as everybody else in your street except some of them have 10kw showers as well, come on man get a grip.

 

[Andy78]

It's a 100 amp, type 2 b 1361 without cutting off the seals, that's what it says on the tin!irate:

So it could be a 60A then ......

I think Dazza has given the best advice of asking your mate for advice. You just seem to be confusing the forum and yourself at the moment .....

 

[ian w j]

No offence but do you know all aspects of electrical wiring? The sparkys on site who I meet can only wire houses, when it comes to star /delta delta 690v and control circuits with relays and plc's, the don't have a Scooby do either! We all have different fields that we are good in and when I am not sure Is ask.:89:

 

[dazza1981]

No offence but do you know all aspects of electrical wiring? The sparkys on site who I meet can only wire houses, when it comes to star /delta delta 690v and control circuits with relays and plc's, the don't have a Scooby do either! We all have different fields that we are good in and when I am not sure Is ask.:89:

I agree to an extent but regardless as to what field your in this is very basic stuff ???
Only you know what your house is pulling so only you can make a decision as to whether your hot tub will overload your supply???
Say for instance your correct and your main fuse is 100 amp, do you seriously think you will pull over 100 amps at any one point????
If you are that worried why dont you switch on everything in your house and clamp it to see what your pulling !!!

 

[ian w j]

Surely when the supply company connect up they have to clearly identify the current rating of the supply! The seals aren't meant to be cut off to find this out when you do an Niceic test are they?

 

[Darkwood]

No offence but do you know all aspects of electrical wiring? The sparkys on site who I meet can only wire houses, when it comes to star /delta delta 690v and control circuits with relays and plc's, the don't have a Scooby do either! We all have different fields that we are good in and when I am not sure Is ask.:89:

With all respect here I panel design build and repair machinery but as part of my job title I strife to ensure im fully aware of any regulation changes and additions and keep up with other fields like domestic / commercial and Industrial installation I was trained in....Ive not done domestic for 10yrs but can still run rings around most regarding the regulations surrounding them, you've spent so long out of the loop you really only have yourself to blame here .... now my constructive advice is use this forum often and just scan the threads and replies often this will build back up what you have forgot... like it or not you no longer can say you are competent in domestic install which leaves a few option ... get outside help in or do a lot of homework and get the reg's book out and your purchase a few books.

Your cutout fuse could be 60amp 80amp or 100amp been the common rating in domestic the carrier stamp of 100amps is its tolerance not what it contains.

You will need to be aware of the nature of your supply as I assume this hot-tub is going outside? Correct me if Im wrong there.

Diversity in the regs is a guide-line and can often be over compensating for actual demand, you know your house and usage if unsure get a monitor maybe free from your energy supplier and monitor your usage...

Lastly give your lass a stern look of disagreement .... today a Hot-tub tomorrow a pearl necklace (Woah ...not that kind .. )

 

[Plonker 3]

Why not take a week if work and use a clamp meter every 10 minutes in your tails to your DB for that week then you will know exactly what current your house is pulling?

 

[Guest77]

No offence but do you know all aspects of electrical wiring? The sparkys on site who I meet can only wire houses, when it comes to star /delta delta 690v and control circuits with relays and plc's, the don't have a Scooby do either! We all have different fields that we are good in and when I am not sure Is ask.:89:

I consider myself an all rounder yes, however that said fair enough I get your point and there has been enough advice in this thread for me to continue further. Lastly as daft as it sounds welcome to the forum mate.

 

[ian w j]

Thought of that, just waiting for the wife to put a wash on, do the dishes, put on the tumble dryer boil the kettle and Hoover up, whilst cutting the grass! All this in the dark with all the lights on!:6:

 

[Plonker 3]

Thought of that, just waiting for the wife to put a wash on, do the dishes, put on the tumble dryer boil the kettle and Hoover up, whilst cutting the grass! All this in the dark with all the lights on!:6:

So you have just answered your own question.

 

[dazza1981]

Thought of that, just waiting for the wife to put a wash on, do the dishes, put on the tumble dryer boil the kettle and Hoover up, whilst cutting the grass! All this in the dark with all the lights on!:6:

With all the heating on full whack, every socket in use, shower on,toaster,every light on,microwave !!!!
I think your understanding what me and the lads are trying to tell you now Ian ???

 

[trev]

Thought of that, just waiting for the wife to put a wash on, do the dishes, put on the tumble dryer boil the kettle and Hoover up, whilst cutting the grass! All this in the dark with all the lights on!:6:

Sounds like she's well trained, did you break many sticks during the process?