Defining what equipment has protective conductor current

[Ben Murray]

Hi all,

I have an engineer who has failed a wall mounted data cabinet because the PDU is hard wired into a switched fused spur, the spur is spurred off a ring main in 2.5/1.5 twin and earth.

He has failed it under regulation: 543.7.203 The wiring of every final circuit and distribution circuit intended to supply one or more items of equipment, such that the total protective conductor current is likely to exceed 10 mA, shall have a high integrity protective connection complying with one or more of the following:
(ii) A single copper protective conductor having a cross -sectional area of not less than 4mm, complying with the requirements of regulation 543.2 and 543.3, the protective conductor being enclosed to provide additional protection against mechanical damage, for example, within a flexible conduit.

My question is, how can you determine the protective conductor current of a piece of equipment? This is a wall mounted cabinet with a few switches in it, no servers pulling high amounts of power and I doubt the cabinet as a whole is exceeding 3.5 mA (Reg 543.7.201) let a lone 10 mA. Unfortunately I am not signing my name to the test results and I need to make sure we're doing things properly.

 

[Barnaby Stedman]

why do you say 2.5/1.5mm is there some parts of the ring on 1.5mm cable?

 

[Pete999]

Hi all,

I have an engineer who has failed a wall mounted data cabinet because the PDU is hard wired into a switched fused spur, the spur is spurred off a ring main in 2.5/1.5 twin and earth.

He has failed it under regulation: 543.7.203 The wiring of every final circuit and distribution circuit intended to supply one or more items of equipment, such that the total protective conductor current is likely to exceed 10 mA, shall have a high integrity protective connection complying with one or more of the following:
(ii) A single copper protective conductor having a cross -sectional area of not less than 4mm, complying with the requirements of regulation 543.2 and 543.3, the protective conductor being enclosed to provide additional protection against mechanical damage, for example, within a flexible conduit.

My question is, how can you determine the protective conductor current of a piece of equipment? This is a wall mounted cabinet with a few switches in it, no servers pulling high amounts of power and I doubt the cabinet as a whole is exceeding 3.5 mA (Reg 543.7.201) let a lone 10 mA. Unfortunately I am not signing my name to the test results and I need to make sure we're doing things properly.

You need an Earth Leakage Clamp Ammeter, (not a cheap item)

 

[westward10]

Have they quoted what the protective conductor current was?

 

[Pete999]

Hi all,

I have an engineer who has failed a wall mounted data cabinet because the PDU is hard wired into a switched fused spur, the spur is spurred off a ring main in 2.5/1.5 twin and earth.

He has failed it under regulation: 543.7.203 The wiring of every final circuit and distribution circuit intended to supply one or more items of equipment, such that the total protective conductor current is likely to exceed 10 mA, shall have a high integrity protective connection complying with one or more of the following:
(ii) A single copper protective conductor having a cross -sectional area of not less than 4mm, complying with the requirements of regulation 543.2 and 543.3, the protective conductor being enclosed to provide additional protection against mechanical damage, for example, within a flexible conduit.

My question is, how can you determine the protective conductor current of a piece of equipment? This is a wall mounted cabinet with a few switches in it, no servers pulling high amounts of power and I doubt the cabinet as a whole is exceeding 3.5 mA (Reg 543.7.201) let a lone 10 mA. Unfortunately I am not signing my name to the test results and I need to make sure we're doing things properly.

Ben does the item of equipment have an details as to the predicted earth leakage? I take it from your post that the Ring Final Circuit RFC has not been wired as per regulation 543.7.2.201 pagev87 On Site Guide 18th Edition

 

[Ben Murray]

Thank you for the replies, I misunderstood the whole picture of the failure and focused solely on this problem, I am human and still learning the vast information the BS hold! Next question is how do I remove a post so I don't get bombarded with replies?

 

[westward10]

I can lock it if you wish.

 

[westward10]

Any chance of knowing the misunderstanding.

 

[Ben Murray]

Please do, but I look forward to using this forum to help me in the future thank you.

 

[Ben Murray]

The circuit is protected with a 32A MCB wired in 2.5 and the PDU flex is in 1.5, so they have recommended reinstalling the circuit with a dedicated supply protected by a 16A breaker.

 

[westward10]

Thread closed at OPs request but has provided an answer to the misunderstanding.