typical earth leakage on a fridge

[adamh]

had my mate the plumber ring me today asking if a ring for sockets stops at the last socket ha i obviously said no that would be a radial etc...
he said its only for 10 sockets to which i replied its all about the loading what is it using... apparently its for 5 fridges and a pot wash which could either be plug in or 6mm after i stopped laughing i said if you were an electrician i would be asking what OCPD you would be using .. b curve etc start up currents and earth leakage to which he replied thats what its on now!! I just laughed and said fair enough ask the "electrician" who is doing the final connections etc what he thinks or pay me to do it , its on a pub refurb btw I assume its now on 1 ring which will no doubt need rcd protection.. so my question is, what is the typical leakage of a fridge i beleive it to be about 3.5mA typical and 6mA on start up? Thanks Adam.

 

[Marvo]

In the old days fridges used to be prone to higher leakage due to the defrost element that operates in a wet area. Nowadays there's no real excuse for them to have higher leakage than any other appliance so I would expect <1mA.
The compressor should have zero leakage current nominally speaking, the motor is hermetically sealed in a dry environment so the leakage on start-up should be lower that during defrost.

 

[Engineer54]

In the old days fridges used to be prone to higher leakage due to the defrost element that operates in a wet area. Nowadays there's no real excuse for them to have higher leakage than any other appliance so I would expect <1mA.
The compressor should have zero leakage current nominally speaking, the motor is hermetically sealed in a dry environment so the leakage on start-up should be lower that during defrost.

Just thinking about your post Marvo, like everything else these days the manufactures always seem to like controlling most fridge/freezers with micro processors and the like, along with other added gizmo's which will ultimately add to a units leakage current.

Had an all singing, all dancing unit in a commercial kitchen on the last project that went U/S, continuously tripping out a DP RCBO during the warranty period. Brought in the manufacturers, who decided to replace with a new unit. Checked the new unit for it's nominal leakage current which was found to be around 6mA, which the manufacturer was pleased with, as on there service data sheet it stated 6.5mA. So i would guess it will depend on the electronics and added goodies on a unit, as to what sort of leakage to expect.

Don't know why, these manufactures can't leave well alone!! ...lol!!

 

[Marvo]

You have a valid point but as you say it's the higher technology items across the board that present with higher leakage currents, if it was just a fridge with a mechanical-analogue thermostat everything would be fine and dandy. Switch mode power supplies are notoriously leaky and add the fact that appliances with some kind of PLC or micro processor control will have surge arrestors/lightning protection/noise suppressors which also often allow slight leakage even under the clamping voltages of said components, before you know it you've got a kitchen full of appliances that are all within individual spec but as a combined load you've got nuisance tripping of the RCD's.

I only see this as getting worse until there's tighter limits written into the codes and regs. Also I have to be honest, I don't know how a manufacturer could specify 6.5mA as being acceptable, they're taking a fat chance if you ask me

 

[Engineer54]

You have a valid point but as you say it's the higher technology items across the board that present with higher leakage currents, if it was just a fridge with a mechanical-analogue thermostat everything would be fine and dandy. Switch mode power supplies are notoriously leaky and add the fact that appliances with some kind of PLC or micro processor control will have surge arrestors/lightning protection/noise suppressors which also often allow slight leakage even under the clamping voltages of said components, before you know it you've got a kitchen full of appliances that are all within individual spec but as a combined load you've got nuisance tripping of the RCD's.

I only see this as getting worse until there's tighter limits written into the codes and regs. Also I have to be honest, I don't know how a manufacturer could specify 6.5mA as being acceptable, they're taking a fat chance if you ask me

As i stated Marvo, this was a commercial unit and a rather large all singing, all dancing one at that. Not one that you could plug into a general distribution circuit, that's for sure!! lol!! Actually looked like a very large American style double door unit except it had three very large doors. Just trying to remember the unit's rating, which i'm pretty sure was around 23/25A running...

As for leakage and harmonic currents getting worse, there are an awful lot of supply companies in the UK, that are very worried about it now!! lol!!

 

[Marvo]

....Just trying to remember the unit's rating, which i'm pretty sure was around 23/25A running...

Wow, 25 Amp is a very large fridge even by commercial standards. I wasn't picturing that size unit from your first post, that's around a 7hp unit which is immense. Even so the same theories apply, the compressor should still be very high IR given it's a sealed motor and a perfectly dry environment.

I also see the harmonics problems caused by cheap psu's becoming more of a high profile issue shortly. They've been very slow to introduce appropriate regs and they're now paying the price with especially the triplens adding considerable strain on supply grids that are already running close to capacity. The manufacturers have gotten away with murder up until now, all good design practices have been sacrificed to keep the price-points low but I think their days are numbered.