UK AC RCD’s C2? Absolutely!

[J Sparks]

Given the advancement in technology and the high amount of potential DC in electrical systems. An AC RCD that won’t work, invokes so many further regulations for circuits that need RCD protection that no longer do! 100% C2 in my opinion

 

[nicebutdim]

You might be able to make such a case for specific installations, but as a blanket statement I'd imagine it would be dificult to back up.

How would you justify coding every Type AC RCD as "Potentially dangerou’. Urgent
remedial action required"?

What potential danger exists in the average home with Type AC protection?

 

[J Sparks]

You might be able to make such a case for specific installations, but as a blanket statement I'd imagine it would be dificult to back up.

How would you justify coding every Type AC RCD as "Potentially dangerou’. Urgent
remedial action required"?

What potential danger exists in the average home with Type AC protection?

The AC RCD is essentially rendered useless due to DC current. So off the top of my head circuits within a bathroom, sockets supplying external equipment, electric showers, cables in walls less than 50mm from the surface…all require RCD protection in a standard home, however if the RCD doesn’t work, how is that not potentially dangerous? I wouldn’t like to be the one justifying my case to the man in the wig over this one!

 

[nicebutdim]

The AC RCD is essentially rendered useless due to DC current. So off the top of my head circuits within a bathroom, sockets supplying external equipment, electric showers, cables in walls less than 50mm from the surface…all require RCD protection in a standard home, however if the RCD doesn’t work, how is that not potentially dangerous? I wouldn’t like to be the one justifying my case to the man in the wig over this one!

Can you clarify if you mean an RCD that won't work as it has failed or an RCD that won't work due to DC current injected by a downstream appliance?

I may have grasped the wrong end of this particular stick, but in my defence your OP is open to misinterpretation and thread title suggests blanket C2 for Type AC protection.

 

[J Sparks]

Can you clarify if you mean an RCD that won't work as it has failed or an RCD that won't work due to DC current injected by a downstream appliance?

I may have grasped the wrong end of this particular stick, but in my defence your OP is open to misinterpretation and thread title suggests blanket C2 for Type AC protection.

An RCD that won’t work due to DC current injected downstream! Apologies, I wouldn’t say a blanket C2 but certainly more common than not in my opinion

 

[nicebutdim]

An RCD that won’t work due to DC current injected downstream! Apologies, I wouldn’t say a blanket C2 but certainly more common than not in my opinion

Wouldn't you generally code any RCD that failed to work, for any reason, as C2?

 

[SJD]

If you read the Best Practice guide #4 for EICR coding (Nov 2022) from Electrical Safety FIrst, it states for "A Type AC RCD installed where a Type A RCD required" to be coded as C3.

 

[nicebutdim]

If you read the Best Practice guide #4 for EICR coding (Nov 2022) from Electrical Safety FIrst, it states for "A Type AC RCD installed where a Type A RCD required" to be coded as C3.

OP has clarified they're referring to an RCD that fails to operate.

 

[J Sparks]

Wouldn't you generally code any RCD that failed to work, for any reason, as C2?

Yes, that’s essentially my point. I’m seeing a lot of people pass over this issue with AC rcds and not even bother coding it. It’s a major issue that’s being ignored by too many!

 

[nicebutdim]

Yes, that’s essentially my point. I’m seeing a lot of people pass over this issue with AC rcds and not even bother coding it. It’s a major issue that’s being ignored by too many!

A failed RCD needs to be replaced, regardless of type of protection provided. I've never encountered anyone who would ignore failed RCD protection.

 

[J Sparks]

If you read the Best Practice guide #4 for EICR coding (Nov 2022) from Electrical Safety FIrst, it states for "A Type AC RCD installed where a Type A RCD required" to be coded as C3.

It also says that coding is entirely at the discretion of the inspector and the document is merely a guide. I would rather be fussy and improve a system than be lazy and have someone’s death on my conscience. Honest question, if you know an AC rcd may not work in a fault situation, explain why you would code it as a C3 and negate the need for someone to fix it. Imagine a child sticks their finger in a lamp holder? But the rcd fails…

 

[westward10]

Someone sticking their fingers into a lampholder may well not bother an RCD.

 

[J Sparks]

Someone sticking their fingers into a lampholder may well not bother an RCD.

An AC rcd*

 

[westward10]

An AC rcd*

Any RCD.

 

[J Sparks]

Any RCD.

Sure…

 

[nicebutdim]

It also says that coding is entirely at the discretion of the inspector and the document is merely a guide. I would rather be fussy and improve a system than be lazy and have someone’s death on my conscience. Honest question, if you know an AC rcd may not work in a fault situation, explain why you would code it as a C3 and negate the need for someone to fix it. Imagine a child sticks their finger in a lamp holder? But the rcd fails…

A short while back we established that you were commenting on failed units, but now the conversation seems to have shifted to RCDs that 'may not work in a fault situation'.

How are you establishing that an RCD may fail to operate?

As for coding being at the discretion of the inspector, that's the sort of argument applied by testers who blanket code insulated CUs as C2.

Coding should be back up by regulations and sound engineering judgement. It should not be whimsical in nature.

 

[westward10]

Sure…

Sure what?

 

[J Sparks]

A short while back we established that you were commenting on failed units, but now the conversation seems to have shifted to RCDs that 'may not work in a fault situation'.

How are you establishing that an RCD may fail to operate?

As for coding being at the discretion of the inspector, that's the sort of argument applied by testers who blanket code insulated CUs as C2.

Coding should be back up by regulations and sound engineering judgement. It should not be whimsical in nature.

It’s common knowledge that DC current in a circuit with an AC RCD impairs it’s ability to work. Domestic properties have numerous electrical items, induction hobs, led lighting, EVCP’s that all can present this within an installation. There are loads of videos on YouTube explaining the logic behind it. It’s in the regs check out 531.3.3! As for sound judgement I’m an electrical technician with an electrical engineering degree and twenty years testing experience. I think I’m suitable to make the decision. There is a reason they are banned in half the world!

 

[nicebutdim]

It’s common knowledge that DC current in a circuit with an AC RCD impairs it’s ability to work. Domestic properties have numerous electrical items, induction hobs, led lighting, EVCP’s that all can present this within an installation. There are loads of videos on YouTube explaining the logic behind it. It’s in the regs check out 531.3.3! As for sound judgement I’m an electrical technician with an electrical engineering degree and twenty years testing experience. I think I’m suitable to make the decision. There is a reason they are banned in half the world!

Yet for most of those 20 years you were completely unaware of the issue, until Youtube broadened your knowledge?

I was hoping for an explanation of your testing process, rather than coding on the basis of assumption and that's the problem I have with this sort of blanket coding. 'Potential' exists for failure of Type A RCDs. Where they are used for fault protection, do you mandate that additional protection be provided on the basis of 'what if'?

While I don't disagree with the basic premise that Type A protection would be preferable, I do disagee with the idea of coding on the basis of assumption where no potential danger can be demonstrated in a particular installation.

A failed RCD needs to be replaced, regardless of whether that failed unit is Type AC, A or other. A working RCD does not need to be replaced, unless evidence exists to suggest that it will fail to operate (whether that be for the reasons you outline or for any other reason). The average house does not have an induction hob or EVCP and basic LED lamps aren't likely to introduce sufficient DC current to prevent operation of a Type AC RCD. In short, while it may be the case that Type AC protection isn't suitable for a modern installation, most homes do not possess what might be considered a 'modern installation'. Coding should be appropriate to each installation inspected.

 

[nicebutdim]

I'd like to qualify my previous comments as the OP probably knows nothing about me and might consider them to be argumentative or harsh. The comments weren't intended to be either, but as an apprentice I find myself disappointed and frustrated when no logic is apparent behind blanket statements.

We're all entitled to our opinions, but equally we should be able to substantiate them as bold opinions are likely to be challenged.

Tl;dr... No offense intended, but I want to learn and want to do so in an informed manner.