in after a cowboy, cooker nearly burnt the house down!

[1shortcircuit]

the onsite guide is an example of 'kiss' and is just a guide

keep it simple stupid

 

[Guest55]

keep it simple stupid

not simple enough apparantly.
;-)

 

[1shortcircuit]

not simple enough apparantly.
;-)

Made me chuckle

 

[ExArmy]

the very last sentance on that page says " the remainder of the installation would require protection by a 100mA rcd"

which implies not every circuit must need 30mA rcd for it to say that ??

not much gratitude there for walking you through your job exarmy ? :-/

sorry if that came accross as me not showing gratitude, i am greatful for all input on this thread and wasn't arguing with you, but i just can't see how page 28/9 clearly lays out the requirements, to me it's consfusing! for a start it says "TT conduit installations". i've had a good poke about the house, not seen any conduit yet. so does that apply?

 

[Guest55]

It doesnt matter what sort of wiring the house has , even if it is in steel conduit or not.
Its only your work that has to be considered , so if you install a cable to your new cooker spur , that has to be 30mA rcd protected , which will mean fitting a rcd at the mains even though theres a 100mA rcd already there.
OR
Fit the new cable in surface trunking then you dont have to fit extra 30mA rcd.

 

[1shortcircuit]

It doesnt matter what sort of wiring the house has , even if it is in steel conduit or not.
Its only your work that has to be considered , so if you install a cable to your new cooker spur , that has to be 30mA rcd protected , which will mean fitting a rcd at the mains even though theres a 100mA rcd already there.
OR
Fit the new cable in surface trunking then you dont have to fit extra 30mA rcd.

I agree with surface mount otherwise you may find yourself having to work around discrimination issues.

 

[edward cooper]

Hi sorry to butt in,

As the cooker is classed as fixed equipment and is over 2kw shouldnt it be on a dedicated radial. Thats just my take on it so please dont shoot me.

Also as its now on its own dedicated radial it will need 30mA RCD protection because if you surface mount it it will look awful and you will get the name John Wayne.

 

[1shortcircuit]

As awful as surface mount is it does serve it's purpose and it's the easiest option for the homeowner to consider.

I think we have all probably installed surface mount at some stage or another? :thumbsup

 

[Guest55]

..................Thats just my take on it so please dont shoot me. Can someone get my gun.

Also as its now on its own dedicated radial Its not on any circuit - he hasnt done the job yet.

it will look awful and you will get the name John Wayne. The mans a legend.

.....................

 

[ExArmy]

is there something that says fixed equipment over 2KW has to be on a dedicated radial? it's just that i wouldn't know how to justify that to the customer, it's only 3.2KW, almost the same as a kettle!

and regarding surface mounting to avoid having to fit RCD, ihave just come accross Reg 411.5:

"cables installed on the surface do not specifically require RCD protection, however, RCD protection may be required for other reasons, for example, for the fault protection, where the earth fault loop impedance is such that the disconnection time for an overcurrent device cannot be met"

 

[steveberry11]

230 volts is just the baseline for design calcs where supply details arent known.
If you know the actual voltage , in this case 250v , then use that value.

230 volts should always be used what happens when the the DNO changes the transformer trappings of carry out switching in the area.

Stick with 230v

 

[1shortcircuit]

"cables installed on the surface do not specifically require RCD protection, however, RCD protection may be required for other reasons, for example, for the fault protection, where the earth fault loop impedance is such that the disconnection time for an overcurrent device cannot be met"

Simple test and compare to max Zs for the protective device

 

[ExArmy]

230 volts should always be used what happens when the the DNO changes the transformer trappings of carry out switching in the area.

Stick with 230v

well they have been talking about it for a while, i suppose it might happen one day...

 

[edward cooper]

i know he has not done job yet. As i have treated it as fixed equipment then I would put it on its own circuit and then because i have done this it will require rcd protection. i do how ever think my post is pretty clear.

 

[spark 68]

is there something that says fixed equipment over 2KW has to be on a dedicated radial? it's just that i wouldn't know how to justify that to the customer, it's only 3.2KW, almost the same as a kettle!

and regarding surface mounting to avoid having to fit RCD, ihave just come accross Reg 411.5:

"cables installed on the surface do not specifically require RCD protection, however, RCD protection may be required for other reasons, for example, for the fault protection, where the earth fault loop impedance is such that the disconnection time for an overcurrent device cannot be met"

Point 1) is in App. 15 in the BGB and is a recommendation.

Point 2) would your 100mA RCD upfront not satisfy the disconnection time for the Zs (you don't say if it is TD or not), although that in itself contravenes Reg 314.

 

[Guest55]

230 volts should always be used what happens when the the DNO changes the transformer trappings of carry out switching in the area.

Stick with 230v

Thats not the guidance given in the IEE electricians design guide when making a detailed assessment.
But im too busy getting drunk to argue it out lol.
;-)

 

[edward cooper]

i was not stating i would not fit rcd i was just quoting what some one else stated. i believe that it needs rcd protecting. If you fit a 3.2kw cooker on the ring without 30ma rcd protection i think your a fool. Dont forget this is a TT system.

a kettle is not fixed equipment and there is no comparison to be made between a kettle that is on for 3 minutes and a cooker that maybe on for three or four hours possibly a lot longer

 

[ExArmy]

Simple test and compare to max Zs for the protective device

it's about 6ohms at the socket next to the cooker which i would spur off, so on a 3036 it would almost certainly not disconnect within 0.4 seconds. if that is the limit for TT? i must admit i've not done an awful lot with TT. yet

 

[sedgy34]

Either put cable in trunking and install a rcd spur if your that concerned

 

[edward cooper]

TT ExArmy disconnection is 0.2sec