Supply for boiler / fridge-freezer?

[Hibbo]

I have given up on the idea of a nonRCD circuit for logistical reasons, so I'm just going to go for an additional RCBO radial.

The question is whether I should put just the boiler on this, or the FF as well?

The boiler is my main concern, and I don't have an enormous freezer full of prime steak or anything. So do I bother putting the FF on the boiler circuit, or just leave it on the kitchen circuit?

I suppose I could boil my ramblings down to the question "how common are FFs for developing earth faults"?

Cheers.

 

[Lectrician]

Its not how common fridge freezers develop a fault - it's how often do the other appliances on the circuit.......hence a defrosted freezer.

Can you not surface mount for the boiler? A drop of conduit is no different to a drop of pipe.

Failing that - it is becoming very popular to drop a straight length of steel conduit down the wall (or up), bushed to the socket back box.

 

[Hibbo]

I understand the reasons for keeping freezers off of RCD. But my concern here is that a fault on the FF could take the boiler out - that's why I asked how often do FFs go belly-up with earth faults.
I do work away so I don't want to return to burst pipes in the middle of winter. Loosing a few bags of forzen veg is not the end of the world for me.

Surface mount at the boiler is not a problem, but it's getting the cable from the CU in the first place. The CU is mounted up high in the hall, so I don't fancy chasing in 8ft of steel conduit. I could (possibly - it's a flat) go above the hall ceiling, but then I've got to get it down again.

I think a dedicated boiler circuit on an RCBO will suffice.

 

[flameport]

But my concern here is that a fault on the FF could take the boiler out - that's why I asked how often do FFs go belly-up with earth faults

Almost never. Freezers and fridges are some of the most reliable appliances available*, since the only real working part (the motor) is in a permanently sealed cannister. The motor also has overheat/overload protection built in.

Far more likely is a fault with the boiler or the associated controls.

*may not apply to useless models with built in icemakers, water chillers, fans or heaters (yes really)

 

[Hibbo]

But my concern here is that a fault on the FF could take the boiler out - that's why I asked how often do FFs go belly-up with earth faults

Almost never. Freezers and fridges are some of the most reliable appliances available*, since the only real working part (the motor) is in a permanently sealed cannister. The motor also has overheat/overload protection built in.

Far more likely is a fault with the boiler or the associated controls.

*may not apply to useless models with built in icemakers, water chillers, fans or heaters (yes really)

Thank you Flameport.

So, the 64,000euro question: Should I put the FF on the boiler circuit, or leave it on the kitchen circuit? What would you do?

 

[Adam_151]

However, sometimes freezer stats can become noisy due to contact wear, such a condition is capable of tripping an RCD even though theres no earth fault as such

 

[ban-all-sheds]

Should I put the FF on the boiler circuit, or leave it on the kitchen circuit? What would you do?

I'd put it on the boiler circuit, and have that one of the ones switchable to be supplied by a generator.

 

[Steve]

But my concern here is that a fault on the FF could take the boiler out - that's why I asked how often do FFs go belly-up with earth faults

Almost never. Freezers and fridges are some of the most reliable appliances available*, since the only real working part (the motor) is in a permanently sealed cannister. The motor also has overheat/overload protection built in.

Far more likely is a fault with the boiler or the associated controls.

*may not apply to useless models with built in icemakers, water chillers, fans or heaters (yes really)

Heaters in fridge freezers arent unusual. Its how they become frost free, and also part of the reason the cooling fins are hidden - they become quite hot when in defrost.

Seperate Fridges and Freezers are indeed very very reliable - a compressor and thermostat. But combine them and reliability drops significantly!!!

In a typical fridge freezer you have 2 thermostats, usually a PCB, sensing thermistors, a fan or 2, motorised baffles, and of course drain heaters, d/f heaters, door frame heaters - any of which can develop a fault.

Buy seperates

 

[ban-all-sheds]

www.SubZero.com

 

[Lectrician]

Many larger (mainly commercial) fridge/freezers use a heater for the chiller.

They cool air to -20 or so for the freezer, and then pull cold air from there and heat it for the chiller.

 

[Steve]

Many larger (mainly commercial) fridge/freezers use a heater for the chiller.

They cool air to -20 or so for the freezer, and then pull cold air from there and heat it for the chiller.

Most domestic fridge freezers work like this. Our old Hotpoint Mistral piece of crap had a fan to cool the freezer. When the fridge needed air, a baffle opened and drew air from the fan. The fan could come on without the compressor being on, so the fridge simply drew "still cold" air from the freezer. The compressor would often kick in soon after to re-cool the freezer.