System Loading Questions:

minty · Apr 29, 2010

My house is fairly well loaded and we have now decided that we want to swap over from a gas stove to a duel fuel cooker. I am concerned about the load that this would present and wondered what would be the best way forward. Our house currently has a 60 amp company fuse and running currently on that is a 10.kwh shower drawing 41amps, a single split Air Con Unit used infrequently drawing 6.9amps, Kettle drawing 10 amps, Washing Machine drawing 8 amps and a dishwasher drawing 11 amps, obviously none of these are used all at the same time but if we add this duel fuel cooker rated at total load of 4.5 kwh that would draw 19 amps if both ovens were in use at the same time, given the fact that the two largest loads would be the shower and cooker using any of the other appliances would tip this over the 60 amps available.

I have spoken to my electrical supplier EDF and they require a Load Survey to be compiled by a Qualified electrician and then would make a decision as to if the house fuse could be uprated to a 80 amp pending on if the line in ( Cable in ) would be up to the job and if not a new line in would be required at considerable cost.
Some people have said just get the new cooker and see how you go but I do not want a situation where I although it would be possible for us to juggle loading i the event of say my kids using stuff when we are not at home cold result in the 60 amp fuse being breached.

Would a 80 amp provide the necessary head room for this loading or should I just get the new stove and see how it pans out ? Also EDF have said I may be required to upgrade the meter tails if they give the go ahead for a 80 amp fuse, would EDF pay for this or does it fall to the householder ?

Any Advise welcome,

marcusone · Apr 29, 2010

Hi Minty

From memory as I dont have the charts to hand, to blow a 60A BS1361 you would need a load of 100A or so for half an hour , or approx 120A for a bit over a minute

Normal domestic use is unlikely to blow a 60A fuse. You might pull high levels of current, but not for too long, diversity sees to that.

Your ovens are thermostatically controlled, you wont be drawing a constant 4kw with both on.

It will be fine.

Should you need the tails to consumer unit upgraded then that would be your responsibility.

Mark

( My understanding but always willing to be corrected ! )

Phil · Apr 29, 2010

you are best off getting an electrician round to price it for you. there is a good list of the guys on here http://www.electriciansforums.net/e...lectricians-your-area-local-electricians.html i would have the electrician change the tails for you rather than the supplier as i have seen some ridculous prices quoted by them for tail upgrades if you need them

acat · Apr 29, 2010

As a very rough rule of thumb if you add up the value of all your circuit breakers and divide by four that will give you an idea of your usage.

Chris

ezzzekiel · Apr 29, 2010

add up and x.4

mogga · Apr 29, 2010

DIVERSITY not the wee nutters from BGT

ezzzekiel · Apr 29, 2010

ha lol- took a while

minty · Apr 30, 2010

Thanks for the answers, regarding what I said , i.e

Would a 80 amp provide the necessary head room for this loading or should I just get the new stove and see how it pans out ?

I of course realise that diversity plays a part in that not everything is drawing constantly, but when you look at say the shower drawing 41 amps that load is constant all the while its in use ! add say this duel fuel cooker using just one oven at 13 amps plus the kettle on for three minutes running another 10 amps = 64 amps plus stuff onstandby = 2 amps = 66 amps the loading is above the 60 amps available, 80 amps seems to be much better headroom as opposed to 60 amps

ezzzekiel · Apr 30, 2010

without doing the math your load is 66a after div applied your well below 60a service fuse (which can handle a lot more anyway)

if you decide to up fuse dno would prob upgrade free your tails would need upgrading by you, but if there 16mm or above dont worry about it.

Jason Smith · Apr 30, 2010

calculator says your gonna be ok mate. However, your on the limit. This is the big picture. As an electrician, would I install a 60 AMP fuse in a modern premises that is likely to want 10kw showers, better ovens etc, answer is No I would not. At christmas, I get a flurry of call outs to customers just prior to the day itself because they are doing all the cooking washing, showering because relatives coming etc.
The fuses in your Board will not blow because the individual wires are not drawing too much current, but collectively they add up to the big fuse. You do notwantto blow this one on christmas evemate.
My advice would be to bring it up to the 21 st century, get upgraded and sleep easy. If you dont every time you buy a new appliance you will be worried. Tails shouldnt cost a lot anyway, you will be upgrading to 25mil Probably over a distance of less than three meters.

Des 56 · Apr 30, 2010

Have faith in diversity
You would be surprised what effort would be required to pop a 60 amp 1361

Must have whacked the enter button then.posted before I was finished

The shower is very unlikely to draw full load.it depends on the mains water pressure,the flow rate,the supply voltage at the time and maybe other factors
Its use is generally for short periods,other loads may have simillar lower than stated consumption,the fridge that comes in now and again,the washer that warms the cold or not so cold water,the list can go on and on

If you do not trust to diversity calculations,monitor the load with a clamp meter using as many loaded appliances as possble ,it can be surprisingly lower than you may think

minty · Apr 30, 2010

Thanks Guys,

When you say bring the installation up to the 21st Century do you mean to get the fuse uprated to 80amps with 25mm meter tails ?

I am also a little confused when i called up my supplier EON, they told me that although were my supplier EDF were my host supplier and as far as getting the 60 amp uprated this would be down to them and not EON.
Having spoke to EDF they told me that the meter tails would need to be upgraded to 25mm by EON ? and that they would have to do as it was a legal requirement as opposed to getting a spark to perform the work.
They also said that the meter tails work would be required prior to the fuse upgrade.

Who is right out of these two ? Can I get a independent spark to uprate the meter tails at my own cost ?

It seems to me that before I do anything I need to get the EDF Load Investigation Form which has to be completed by a qualified Electrician sorted, then send it back to EDF who then carry out a study of my local network and possibly a site visit to determine the viabilty of the fuse upgrade.

If permission is given then get the meter tails changed and then ask EDF to increase the 60amp to 80amp so as to avoid any possible issues, does this seem the best route for my situation ?

minty · Apr 30, 2010

Hi Des,

Sorry I thougt that I had already said I have monitored the load at the fuse with my clamp meter and here are the actual readings of what my appliances impose.

Air Conditioning 6.9 amps

Shower 41 amps

Kettle 10 amps

Washing Machine 8 amps

Dishwasher 11 amps

Cooker 19 amps if all loaded

Main oven 13 amps

Standby Current 2 amps i.e Video, Sky box, CCTV, Fridge & Freezer, those two loads upscaling
when Compressors first start

The cooker loads are for the new cooker showing just main oven and full load of both ovens is used at the same time. Thanks for your input !

Jason Smith · Apr 30, 2010

minty said:
Thanks Guys,

When you say bring the installation up to the 21st Century do you mean to get the fuse uprated to 80amps with 25mm meter tails ?

I am also a little confused when i called up my supplier EON, they told me that although were my supplier EDF were my host supplier and as far as getting the 60 amp uprated this would be down to them and not EON.
Having spoke to EDF they told me that the meter tails would need to be upgraded to 25mm by EON ? and that they would have to do as it was a legal requirement as opposed to getting a spark to perform the work.
They also said that the meter tails work would be required prior to the fuse upgrade.

Who is right out of these two ? Can I get a independent spark to uprate the meter tails at my own cost ?

It seems to me that before I do anything I need to get the EDF Load Investigation Form which has to be completed by a qualified Electrician sorted, then send it back to EDF who then carry out a study of my local network and possibly a site visit to determine the viabilty of the fuse upgrade.

If permission is given then get the meter tails changed and then ask EDF to increase the 60amp to 80amp so as to avoid any possible issues, does this seem the best route for my situation ?

In my opinion it is. you will have the capacity not to worry then. At the moment your trying to drive up AMP hill with a small engine.( I like that one !! gonna use that again- I claim its originality )
your 60 AMP fuse will have seals on it, that can only be broken by the service provider (depending on where you live ! ) and putting in new tails should take all of a hour depending on the run- it therfore makes sense for the local electricity board to do this all in one hit and re seal.