Is this safe

[Robojin]

Have been asked to look at an installation as a favour to an old friend I have not seen for some time

When I investigate it seems that when the kitchen was installed the AGA in this house was connected to the kitchen ring :|

About 3-4 months back the fused outlet that the AGA (looks like connect by 26A flex to me, and can't tell if DP due to limited access) was connected to blew while they were out (only the AGA was on), so far as I can gather it was a partial melt, AGA service came out and replaced the SFU, and rightly pointed out that this should be on it's own supply, a fair point, it's also been tucked behind the units with access only from behind pull out draws, so takes a deconstruction to get full access

When I look at the board it's 3P, with no apparent spare MCB's, 3P is deffo an area I don't wish to touch as it's outside my competence

so the question is, "is it safe?", this has been in place for around four years, they have no idea why or can't recall if the engineer said why the FSU blew, the instructions state 30A on 6mm, yet the AGA guys seem to have wired with HR which looks like 26A

It's is on a 32A, but so is every other Kitchen appliance so I think it would be difficult even allowing for diversity not to overload the the MCB with everything on, yet in the two years since they moved in it has never tripped :|

Showing my lack on 3P knowledge, if a way were found to run a 6mm feed, would it need to be on the same phase due to the possibility of 415v, or am I confusing myself?

Just to reiterate I know this is not an ideal installation for a number of reasons but is it unsafe?

 

[binky]

Any photos??? Check wattage of AGA as a starting point. If it hasn't been blowing the MCB then all is possibly well????

Daft question but are you sure its 3Phase, as this is abit unusual for domestic property, though many have 3Phase consumer heads in situ, but not necessarily in use.

 

[steptoe]

Q1

WTF is HR that looks like 26a ?

a size would be more appropriate

and what is the rating plate of the "AGA" state.? I assume you refer to a modern type that is all electric, or electric/gas, or electric/oil, rather than the original that required no electric whatsoever, just wood and coal.

AGA on its own dont mean too much.

more info needed ,

 

[Badger]

i reckon robojin means it h107 flex in 2..5mm or 6mm from the manufacturer

 

[AAAMUSEMENTS]

Q1WTF is HR that looks like 26a ?

a size would be more appropriate

and what is the rating plate of the "AGA" state.? I assume you refer to a modern type that is all electric, or electric/gas, or electric/oil, rather than the original that required no electric whatsoever, just wood and coal.

AGA on its own dont mean too much.

more info needed ,

Indeed, most recent AGAs (and variants - ESSE, Stanley etc.) apart from the all electric one would be fine on a normal FCU - the maximum required was to operate an oil pump/blower, electronic ignition, water pump (often separate anyway) and timer module/thermostats.

 

[Robojin]

Any photos??? Check wattage of AGA as a starting point. If it hasn't been blowing the MCB then all is possibly well????Daft question but are you sure its 3Phase, as this is abit unusual for domestic property, though many have 3Phase consumer heads in situ, but not necessarily in use.

No question this is 3 phase with L1, L2 and L3 on the incomers, and labelled with Red, Blue and Yellow on the MCB's

It's a big house with a pool, the heat/pump unit is massive and has it's own 3P MCB

 

[Robojin]

Q1WTF is HR that looks like 26a ?

a size would be more appropriate

and what is the rating plate of the "AGA" state.? I assume you refer to a modern type that is all electric, or electric/gas, or electric/oil, rather than the original that required no electric whatsoever, just wood and coal.

AGA on its own dont mean too much.

more info needed ,

WTF is WTF

Sorry steps, the access to this is at the back a unit with draws via a 4" hole, HR = heat resistant, to be honest I'm guessing it's size based on it's apparent size, my point was it did not look like anything larger

Yes electric

 

[Robojin]

i reckon robojin means it h107 flex in 2..5mm or 6mm from the manufacturer

I meant that the manual stated that it should be on single phase 30A in 6mm, the cable I could see was to the AGA, and switching the MCB off confirmed it was on the kitchen ring

There was no reference in the manual to wattage so I could not work out max demand, however 30A would imply <7kW

 

[Robojin]

Indeed, most recent AGAs (and variants - ESSE, Stanley etc.) apart from the all electric one would be fine on a normal FCU - the maximum required was to operate an oil pump/blower, electronic ignition, water pump (often separate anyway) and timer module/thermostats.

All electric, the hob is on a separate supply

When AGA serviced this 3 months back, they installed a box that saves power by switching it off for periods

Having discussed the running costs, no way would I contemplate an AGA, had the impression it costs

 

[steptoe]

Ive installed 3ph industrial ovens that only need a 2.5mm cable,

depends if its 7kW total, or per ph,

sorry if I sounded a bit short before, just read some really stupid posts elsewhere.

remember, if its on the kitchen ring then it CANT be 3ph,

it may be like numerous normal cookers, that have a 3ph kind of connection system, but when you actually remove the coverplate they have a link and a diagram as to how single ph connection is acceptable.

EDIT:

re-read again,

sorry,

sounds like it just needs a simple separate cooker supply to it, as any normal cooker would.

remember, its the hob takes the juice, not the oven.

 

[sparkytim]

Hi

If this requires a 32 Amp 6mm supply then it should NOT be on the Kitchen ring main cct. and would explain why it has burnt out the FCU.

It requires a new independant circuit and sounds like your friend should get in a registered Electrical Contractor to sought it out ASAP.

 

[Robojin]

Ive installed 3ph industrial ovens that only need a 2.5mm cable,depends if its 7kW total, or per ph,

sorry if I sounded a bit short before, just read some really stupid posts elsewhere.

remember, if its on the kitchen ring then it CANT be 3ph,

it may be like numerous normal cookers, that have a 3ph kind of connection system, but when you actually remove the coverplate they have a link and a diagram as to how single ph connection is acceptable.

EDIT:

re-read again,

sorry,

sounds like it just needs a simple separate cooker supply to it, as any normal cooker would.

remember, its the hob takes the juice, not the oven.

The Hob is on a 40A as I recall

Again back to my question I know this is not an ideal installation, but would you go to the aggravation and cost installing a new circuit?, in this case my friend is a victim of the recession so would have juggle the books to pay for this, aware of what AGA said and would replace if unsafe

Without the old FSO it's hard to know if this was just an FSU failure or a loose connection

 

[Riggy]

Hi If this requires a 32 Amp 6mm supply then it should NOT be on the Kitchen ring main cct. and would explain why it has burnt out the FCU.

It requires a new independant circuit and sounds like your friend should get in a registered Electrical Contractor to sought it out ASAP.

I agree that if the manufacturers instructions say 32A supply on 6mm then that's what it should have.

However: You comment above about this explaining why it burnt out the FCU is utter rubbish!

If the AGA drew more than the fuse rating, the fuse would blow, it wouldn't burn out the FCU.

Much more likely is that the AGA load is around the 13A mark and there was a loose connection in the FCU.

Back to the OP's original question of is it dangerous? - No, it's not good practice but if all the connections are tight and the cpd's are rated correctly for the cables they are protecting, it's safe.

 

[Robojin]

Hi If this requires a 32 Amp 6mm supply then it should NOT be on the Kitchen ring main cct. and would explain why it has burnt out the FCU.

It requires a new independant circuit and sounds like your friend should get in a registered Electrical Contractor to sought it out ASAP.

I agree that's what the instructions state, but why would AGA install/leave a cable to the FSU that appears to be about the dia of a 26A lead (so far as I could tell)

Is this the only reason for failure, seems to have been in place for 4+ years

I have told him I will not touch it, because I don't have experience with 3P, and needs a contractor who works in this area, he's not the the type to cut corners, if it needs doing he will get it done correctly

 

[sparkytim]

Hi Riggy

If you had seen the number of FCUs BURNT OUT from carrying even 13 Amp loads for extended periods of time as I have, then you would know that my comment was not rubbish.

Thats why Immersion heaters should be on 20 Amp DP not FCU, Fuse carriers just can not handle it.

If manufacturer specifies 6mm 32 Amp circuit then why would any one try and wire it thru a FCU of the ring main?

 

[Robojin]

I agree that if the manufacturers instructions say 32A supply on 6mm then that's what it should have.If the AGA drew more than the fuse rating, the fuse would blow, it wouldn't burn out the FCU.

Much more likely is that the AGA load is around the 13A mark and there was a loose connection in the FCU.

Back to the OP's original question of is it dangerous? - No, it's not good practice but if all the connections are tight and the cpd's are rated correctly for the cables they are protecting, it's safe.

This was my view, I'd expect the fuse to blow, and many times, which it has not

A loose connection was my thought to explain the failure

Of more concern is this is a high usage circuit if the AGA's draw was more than 13A

e.g. Kettle, FFreezer, fridge, Dish washer, 2x Micro Waves

Told him to try an avoid the whole lot on at once, however that's the point of an MCB surely

 

[Badger]

Hi RiggyIf you had seen the number of FCUs BURNT OUT from carrying even 13 Amp loads for extended periods of time as I have, then you would know that my comment was not rubbish.

Thats why Immersion heaters should be on 20 Amp DP not FCU, Fuse carriers just can not handle it.

If manufacturer specifies 6mm 32 Amp circuit then why would any one try and wire it thru a FCU of the ring main?

:Applaud :Applaud

 

[steptoe]

your only solution here(I think0, and assuming your kitchen ring main is on a 32a mcb ring........

is to simply install a little 1way board with a 32amcb(or DP32AMP MCB) for the oven, put it in the cupboard and spur it off the kitchen ring.

its the only way to do this without a new circuit, remember, you must "follow manufacturers instructions"

Im still at a bit of a lose as to how an oven requires 32amps..... though.

 

[Robojin]

Hi RiggyIf you had seen the number of FCUs BURNT OUT from carrying even 13 Amp loads for extended periods of time as I have, then you would know that my comment was not rubbish.

Thats why Immersion heaters should be on 20 Amp DP not FCU, Fuse carriers just can not handle it.

If manufacturer specifies 6mm 32 Amp circuit then why would any one try and wire it thru a FCU of the ring main?

Dare I say it, "Kitchen fitters would" :coat

 

[tom1]

what kw is the oven and hob?