RCBO socket circuit tripping.

[GBDamo]

I'm stuck here fellas.

I have a radial with only one double socket outlet in 2.5mm T&E on a 20A RCBO running five meters in surface mounted trunking. TN-S, R1 and R2 good, 243V measured, Ze 0.12, Zdb 0.29, Zs 0.36, IR all +200MOhms.

RCD trip tests all ok at 0 and 180 and ramp 24mA.

Now these sockets are only used for one thing, two 580W water distillers.

Both have been clamped during operation and are drawing 2.4-2.6A as expected.

Both have been IR tested L-E & N-E and +200MOhms.

I am stumped to the point where I may run in a new socket on a new RCBO, cost not an issue the customer just wants it stopped.

My concern is the issue could be with one or both the distillers units and not the circuit.

I don't have a low current clamp meter so cannot measure earth leakage directly.

Any ideas where to look next, I'm still on the job by the way.

 

[Charlie_]

First thoughts are towards faulty distillers..
Have you tried plugging in other appliances?

 

[GBDamo]

First thoughts are towards faulty distillers..
Have you tried plugging in other appliances?

I'm leaning that way too but cannot think of any definitive way of proving it.

I think it's happening when there thermal overload kicks in, i.e. when they're run dry as they often trip overnight.

I don't want to test that as it may damage the kit but it's the only theory I have at the moment.

I think the customer knows this as they have had them put on a dedicated circuit so as not to take down other areas.

 

[Charlie_]

Can they be put on FCUs and change RCBOs to MCBs ?

 

[Octopus]

As a "controlled test" replace the RCBO with a MCB for a couple of nights and see what happens?

 

[SparkyAndGeorge]

Most likely faulty appliance. How often is it tripping, instantly or randomly? Seen something like this before even though it recently "passed" all its PAT tests. As above swap rcbo for mcb and replace socket for T earth and mark up.

 

[Stspark]

Defiantly points to a faulty appliance. A PAT wouldn't necessarily pick this up though, the equipment is likely 'safe' to pass PAT. Could be worth contacting the appliance manufacture.

 

[GBDamo]

Can they be put on FCUs and change RCBOs to MCBs ?

Cable routing allows for it the only problem I have there is the plugs and power cords are sealed.

 

[GBDamo]

Most likely faulty appliance. How often is it tripping, instantly or randomly? Seen something like this before even though it recently "passed" all its PAT tests. As above swap rcbo for mcb and replace socket for T earth and mark up.

What's a T earth? Auto correct fail?

 

[Strima]

I think it's happening when there thermal overload kicks in, i.e. when they're run dry as they often trip overnight.

Turn them off overnight and see what happens.

 

[GBDamo]

Most likely faulty appliance. How often is it tripping, instantly or randomly? Seen something like this before even though it recently "passed" all its PAT tests. As above swap rcbo for mcb and replace socket for T earth and mark up.

Defiantly points to a faulty appliance. A PAT wouldn't necessarily pick this up though, the equipment is likely 'safe' to pass PAT. Could be worth contacting the appliance manufacture.

Just passed PAT test..

 

[Charlie_]

Nothing wrong with removing sealed plugs, happens all the time with washing machines, etc.
Are the units easily serviceable?
Do they have spare parts?

 

[Charlie_]

As there any other temperature control apart from the thermal cut-out?

 

[GBDamo]

Turn them off overnight and see what happens.

If only they'd listen.

I am looking for a manual as we speak as I cannot see how they control other than thermal trip.

Aquadist Euronda

 

[GBDamo]

As there any other temperature control apart from the thermal cut-out?

Not that I can see, no.