UK RCD nuisance tripping

[AW2022]

At my place of work we have just had multiple LED advertisement screens fitted outdoors, the company specified 16amp RCBO’s for each set of screens. On powering up, the circuits were nuisance tripping due to earth leakage. So the company who installed swapped the rcbo for MCB’s.

The screens themselves, and the frames they are mounted on can be touched by the public but the commando plugs and wiring cannot.

In this situation, is it acceptable to use MCB’s and remove the use of RCD’s due to nuisance tripping as the screens themselves are only going to be operated by skilled persons.

Some of the circuits have over 100mA leakage.

Installing more circuits would help but these screens are pre made in sections to accommodate a single 16amp supply. This would be up to the manufacturer to resolve.

 

[DPG]

That's a lot of leakage. Is it within tolerances for the screens? How many screens per RCBO?

 

[Mike Johnson]

Was it your company that specified 16amp RCBO's for the screens or the manufacturer? if it was the manufacturer then it's their problem to resolve, is the replacement MCB supplied from an RCD? RCBO's are different to RCD's from your post you seem to think they are the same.

 

[AW2022]

1 10m screen per feed made up of 4 smaller sections, and multiple CPU’s in each section. I didn’t install the system but I am responsible electrically for the whole site and would ideally like them on RCBO’s, but need a resolution to take to the suppliers. I am concerned our fix wire periodic test will pull them.

 

[AW2022]

No RCD protection at all from main panel currently.

 

[DPG]

I think you need to know the leakage current per screen from the manufacturer of the screens. They should be able to tell you this.

 

[Mike Johnson]

I am not sure of the regulations for commercial premise's with public access, but would have thought at least one RCD was mandatory.

 

[westward10]

Probably would have made sense to fit either more than one circuit to spread the leakage or install a distribution board within the unit for several socket outlets on separate RCBOs. This is down to the supplier if they gave you the specification for the supply they must have done this before.

 

[AW2022]

They have done this before and have removed RCBO’s after the installation at other sites. I guess I will just have to put it on the manufacturers to come up with a solution. I just wanted to make sure there wasn’t a regulation I had missed that would allow omission in that circumstance, before I have a meeting with them to discuss.

 

[AW2022]

Probably would have made sense to fit either more than one circuit to spread the leakage or install a distribution board within the unit for several socket outlets on separate RCBOs. This is down to the supplier if they gave you the specification for the supply they must have done this before.

There is a total of 56 16amp circuits. That number is what they specified they needed. In reality they probably needed a lot more.

 

[westward10]

How many 16A sockets are within each unit or is it one unit.

 

[AW2022]

How many 16A sockets are within each unit or is it one unit.

1 per unit, the obvious answer would be to install more circuits and have them split the CPU’s up in to multiple circuits per unit.

 

[westward10]

Put an internal distribution board in.
Are these for your benefit these screens or are they renting space.

 

[pc1966]

Are they permanent structures, or do you have to be able to move them around and unplug them, etc?

If fixed wiring and no risk of cable damage, etc, you could avoid the RCD but really would be looking at high-integrity earthing (two separate earths, no common fixing screws, etc) due to the huge leakage current.

 

[hydrocarbonPrimate]

They should have RCD protection if they can be touched by the public.

Are these LED displays lile commercial monitors or an LED matrix?

Does the LED array have its own power supply or is it in strings and powered by main voltage? Reason being if they are powered like that it will cause a halfwave DC component and could be why your getting tripping.

 

[davesparks]

They should have RCD protection if they can be touched by the public.

Which regulation would that be?

 

[davesparks]

RCBO's are different to RCD's from your post you seem to think they are the same.

RCBO's are one of the many types of RCD

 

[Mike Johnson]

Are you saying they are the same?

 

[DPG]

Are you saying they are the same?

RCD is a group of devices. RCBOs are one particular type of RCD.

 

[westward10]

I think the OP is well aware of the differences.