E

Electricalserv

Went to a board change today. Weighed it up did usual tests. Went into kitchen......

Oven on plug into Kitchen ring and Hood wired directly into cooker circuit. Kitchen fitter - no paperwork!

What do you think guys. Refuse the board change unless they want remedials done?? or go ahead as its only the board that I'm touching..... They don't want a periodic.

Also I/R test on whole installation came back as 1.15 mohms very low, But still a pass....

Also 4 lighting circuits into one 5 amp fuse, house is massive with plenty of lights...burn marks all over fuse. They said lights always go off when the have parties at new year....I wonder why??? lol Absolute cowboy mess.

What do you guys think walk away or just do the board change?
 
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Yeh 3036

My main worry is the oven on the kitchen ring. A 30amp fuse seems to have held it though, with no problems. Why anybody would plug the oven into the ring and wire the hood to the cooker cable is an absolute wonder.
 
The ESC guidance on changing CUs says "circuits that are defective or non compliant with the requirements of BS7671 in a way that would result in real and immediate danger must not be connected to the consumer unit"

It also says "Any defects found in reconnected circuits must be recorded on the EIC covering the replacement of the CU, as required by reg 633.2"

From what you have said I do not think it is a real and immediate danger so go ahead and put non compliances and action needed on EIC. Also point out they may have more problems with the lights tripping as MCBs are more sensitive.
 
Has anyone came across these ovens that can go on a 13 amp plug, straight into a ring? I'm told they can go straight onto the ring!


KFH I think the lights will be o.k. Il split them to seperate mcb's for each circuit. There was obviously an overload because all lights where on and only a 5 amp fuse protecting it!
 
Hello

some ovens come with a plug, single ovens. The thing about them is, even if you add all the bits up (grill, oven) ...it's never really running at full tilt like, a kettle for example, which is why in the regs you work out the values using the first 10A and then 30% of the rest (for one case).

I saw a rangemaster spurred off the kitchen ring this week.

In the booklet with the oven it's total combined load is about 16kW. yes 16kW. And it has never tripped the 32A breaker, even though that adds up to 60 odd amperes.

!
 
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Hello

some ovens come with a plug, single ovens. The thing about them is, even if you add all the bits up (grill, oven) ...it's never really running at full tilt like, a kettle for example, which is why in the regs you work out the values using the first 10A and then 30% of the rest (for one case).

I saw a rangemaster spurred off the kitchen ring this week.

In the booklet with the oven it's total combined load is about 16kW. yes 16kW. And it has never tripped the 32A breaker, even though that adds up to 60 odd amperes.

!

I just don't like the idea of having an oven on a ring at all....Yes I now see there are the 13 amp plug in ovens but for me its just not good for the ring!

Why the hood has been wired to the previous cooker circuit I don't know!

I think they seem to think once the CU is changed the EIC cert will be ok to sell up!!!!

What do you guys think in regards to the 1.15 mohm I/R test. I know its a pass but it does require more investigation and I'm dreading telling them that I may need to rewire their lights or any other circuit before the new board goes in.
 
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I just don't like the idea of having an oven on a ring at all....Yes I now see there are the 13 amp plug in ovens but for me its just not good for the ring!

Why the hood has been wired to the previous cooker circuit I don't know!

I think they seem to think once the CU is changed the EIC cert will be ok to sell up!!!!

What do you guys think in regards to the 1.15 ohm I/R test. I know its a pass but it does require more investigation and I'm dreading telling them that I may need to rewire their lights or any other circuit before the new board goes in.
its plain to see why the hood is on the cooker circuit,to make sure you dont over load the ring simples !!!!
 
To be fair once you tested the individual ccts you will find the lowest proberbly above 2 M ohms .

As for the oven I would be more concerned at the rating of it and what the manufacturer recommends.

IMO I would't be happy putting a plug on anything over 2500 w as I would want it on its own cct.

I know the guide is not to put ovens over 2000w on the ring as per appendix 12 of the regs.
 
To be fair once you tested the individual ccts you will find the lowest proberbly above 2 M ohms .

As for the oven I would be more concerned at the rating of it and what the manufacturer recommends.

IMO I would't be happy putting a plug on anything over 2500 w as I would want it on its own cct.

I know the guide is not to put ovens over 2000w on the ring as per appendix 12 of the regs.

Thats my concern, Im not happy putting a new board in and getting a phone call everytime the mcb trips. The kitchen is spotless brand new tiles etc. A rewire of it just isn't an option.

I'd like the opinions of as many as possible on this! What should I put on the cert etc
 
I've seen quite a few ovens (especially single ovens) which are rated at 3kW or less and are provided with a moulded plug which therefore seem to be designed to be plugged in to a 13A socket on a ring main.

In this situation, all you're certifying is a ring main with sockets on... if the owner decides to plug in an appliance (in this case an oven, but you're not to know that) which the manufacturer has provided with a plug, that's up to them, IMO.
 
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Remember when IRing the board you're measuring all the circuits in parallel, so (assuming the juice isn't mashing my brains) the average reading (or each cct has the same IR ohmage) for each circuit will be 1.15Mohm * the number of circuits, eg 10 ccts = 11.5MOhm.

Someone let me know if I'm wrong so I can delete this.
 
The IR reading for the board is looking at all the circuits in parallel - this means that the overall IR reading will be lower than each and every individual circuit reading.

Put another way, if the whole board reading is good, all the circuits must be good too. But if the overall reading is too low for compliance, it's worth checking each circuit separately because each circuit might be compliant, even if their combined reading is not.

I can't remember the exact maths right now, but that's the gist of it
 
1/Rt = 1/R1 + 1/R2 + 1/R3 etc

So individual tests give say 10 M, 15M ,5M,20M,6M,12M, 12M

1/10 + 1/15 + 1/5+ 1/20+ 1/6 + 1/12 + 1/12

1/Rt = 0.1+ 0.067 + 0.2 + 0.05 + 0.167 + 0.083 + 0.083 = 0.75

Rt = 1/0.75 = 1.33 M ohms

So the lowest reading brought down the globle reading.

Hope this makes sence.
 
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1/Rt = 1/R1 + 1/R2 + 1/R3 etc

So individual tests give say 10 M, 15M ,5M,20M,6M,12M, 12M

1/10 + 1/15 + 1/5+ 1/20+ 1/6 + 1/12 + 1/12

1/Rt = 0.1+ 0.067 + 0.2 + 0.05 + 0.167 + 0.083 + 0.083 = 0.75

Rt = 1/0.75 = 1.33 M ohms

So the lowest reading brought down the globle reading.

Hope this makes sence.

Ah yes, I remember now...!
 
by eck tony, thats a fair old bit of a sum for this time of night after beer. but i see the point. you can have 10 circuits, each 10M. in parallel they will read 1M. that's my level of maths at the moment.
 
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Imo they should have a full periodic inspection,pre change,and if anything comes up that would cause issues then its all extras,bonding included,dont be afraid to discuss any issues with them,remember that your the professional and can give as much advice as you need.
 
There's nothing wrong with these new ovens on plug tops. Especially the moulded ones because that's obviously how it's designed. We've just got to get used to not seeing these big clunky things
 
Hope i have not missed something here, but could the appliance be gas with electric ignition.
As for the extraction on the cooker circuit,.... the motor must be huge
 
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My main worry is the oven on the kitchen ring. A 30amp fuse seems to have held it though, with no problems. Why anybody would plug the oven into the ring and wire the hood to the cooker cable is an absolute wonder. You check all the instrument of kitchen with the passage of time . Your problem is remove easily.
 
Hello

some ovens come with a plug, single ovens. The thing about them is, even if you add all the bits up (grill, oven) ...it's never really running at full tilt like, a kettle for example, which is why in the regs you work out the values using the first 10A and then 30% of the rest (for one case).

I saw a rangemaster spurred off the kitchen ring this week.

In the booklet with the oven it's total combined load is about 16kW. yes 16kW. And it has never tripped the 32A breaker, even though that adds up to 60 odd amperes.

!

69.56 amps in fact! thats impressive
 

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