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Topic Title: Access only by a competent person
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Created On: 10 October 2012 01:48 PM
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 10 October 2012 01:48 PM
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Jason555

Posts: 8
Joined: 17 January 2011

I am undertaking an 'Electrical Installation Condition Report' of an industrial distribution cabinet.

The cabinet is fed direct from an 11KV/415v substation on site. And the cabinet feeds 40 individual 3 phase machines each on individual 3 phase breakers/radial circuits.

The cabinet itself is manufactured in Switzerland by the same company that manufactures all the machinery on site; it's a specially made distribution cabinet

The cabinet is metal and totally enclosed, approx 6ft by 2ft. It has a full size hinged door on the front which requires a cabinet key to open it, (I believe the key is called a Double Bit No.5 Key). Once opened all the breakers are exposed and so are all the busbars. The door can be opened whilst everything is live.

Should all the live busbars be covered/barrier/guarded or is this acceptable as using the double bit No.5 key constitutes "access only by a competent person"?
 10 October 2012 02:16 PM
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OMS

Posts: 19900
Joined: 23 March 2004

Why would you think access should be limited to a "competent person" given the panel enclosure is only accessible via the use of a key or tool.

try 416.2.4(i)

Regards

OMS

-------------------------
Failure is always an option
 10 October 2012 03:46 PM
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Jason555

Posts: 8
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Thanks OMS

Maybe I should rephrase my question:

Should live busbars be barriered inside an enclosure?
Until now, I've never come across a situation where they're not.

I feel reg 416.2.4 sits alongside my question but doesn't necessarily answer it.

Reg 416.2.1 states; live parts shall be inside enclosures, but not barriered inside enclosures.

As for me mentioning, "access only by a competent person" in my previous post, I guess I was just over interoperating reg 416.2.4.
 10 October 2012 04:01 PM
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AJJewsbury

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Reg 416.2.1 states; live parts shall be inside enclosures, but not barriered inside enclosures.

Exactly - the regs don't say you need barriers inside enclosures - hence you don't.

- Andy.
 10 October 2012 04:05 PM
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OMS

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Well, as good practice, yes they should, but equally there is no problem if they aren't.

refering to BS 7671 probably isn't the best approach either - this is either a control panel or switchgear - covered by equipment standards.

I would imagine the client has a policy on who is allowed to access this panel - now that may refer to competent persons of course.

Personally, i would expect something like a perspex intermediate barrier to be present that covers the bars but still retains access to the breakers - but that's just an opinion.

A label on the door warning of direct access to live parts might also be a good idea.

Contrasted against BS 7671 though, I'd say it was entirely compliant.

Regards

OMS

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Failure is always an option
 10 October 2012 04:23 PM
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slittle

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I'm with OMS on this, I'd rather see a perspex barrier than not although if you are competent enough to have key access to such a panel then you should be well aware of what's inside it.

That said the perspex would help prevent those "little mishaps" that keep our friends at the HSE in paperwork.

I'm assuming there is some sort of incoming isolation on this panel for maintenance purposes ??


Stu
 10 October 2012 04:40 PM
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OMS

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I'm assuming there is some sort of incoming isolation on this panel for maintenance purposes ??


I think it's source end Stu - hence the perspex to keep fingers off the hurty bits comment

we could go nuts and have a trapped key at the source end isolator that can only be removed when off, that is then free to open the cabinet door - and with the key out, you can't re-energise the isolator - OTT for minimum compliance but I've designed a few like that over the years

regards

OMS

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Failure is always an option
 10 October 2012 04:45 PM
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slittle

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We could but don't you find the darwinian solution much easier (providing it's not your name on the design)

Stu
 10 October 2012 05:07 PM
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OMS

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LoL - I've tried putting "Protection by Darwinian Selection" on a designers risk assessment once - the elf 'n safety chaps didn't see the humour (or the irony)

I guess it's a good point though Stu - it has to be said that most designers have at least one on on the risk transfer process that results in OTT design solutions because we often have no idea of the "quality" of the installers or maintainers

regards

OMS

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Failure is always an option
 10 October 2012 06:41 PM
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jcm256

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I think all may be skipping past or jumping over 416.2.1 (1) with the screwdriver to 416.2.4 (1). For example quarry operative cheating the electrical mechanical interlock resetting overloads (and they do) would be a stackable offence. Insurance inspections in industrial control panels, switch panels even when switched off, if shrouds or a cover were not fitted on the main incomer live connections, an immediate urgent notice would be issued. The Competent Person must be electrical, a summery of that person is below: but needs supplemented by e level in most cases. F to h certainly for HV.


(a) Appointed Person
A person, normally not from electrical staff, who is authorised by the Senior Electrical Authority to perform specified duties on Electrical Equipment, e.g. starting and stopping electric motors and synchronising of generators.

(b) Competent Person
A person who has sufficient technical knowledge or experience to perform Mechanical Work
or Non-electric Work safely.

(c) Authorised Person (Electrical) [AP (E)]
A Competent Electrical Person, Authorised Electrical Person or Senior Authorised Electrical Person.

(d) Competent Electrical Person (CEP)
A person, authorised by the Senior Electrical Authority to carry out specified Low Voltage Operations on Electrical Power Systems and Work on Electrical Equipment

(e) Authorised Electrical Person (AEP)
A Competent Electrical Person, authorised by the Senior Electrical Authority to supervise or to carry out specified Operations on High Voltage and Low Voltage Electrical Power Systems and Work or Testing on Electrical Equipment.
The authorisation may include the authority to receive a Sanction For Test, issue and cancel Limitation Of Access and to perform the necessary safety procedures associated with such
Work or Testing.

(f) Senior Authorised Electrical Person (SAEP)
An Authorised Electrical Person, with minimum Job Group 6, authorised by the Senior Electrical Authority to initiate Work or Testing on High Voltage Electrical Equipment. The authorisation includes the authority to issue and cancel all Electrical Safety Documents
and to perform the necessary safety procedures associated with the issue and cancellation such documents.

(g) Responsible Person Electrical (RPE)
An Authorised Electrical Person or a Senior Authorised Electrical Person, appointed by the Holder/Operating Department, who is responsible for electrical safety and the control of
Work and Testing within a specified geographical area or facility.

(h) Senior Electrical Authority (SEA)
The Head of Electrical Engineering, who has an electrical engineering degree and is responsible for developing BSP's
Electrical Safety Rules and overseeing the assessment of electrical competency and training and experience of persons Operating, Working and Testing on Electrical Equipment.
 10 October 2012 07:17 PM
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Jason555

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Thanks for your help gentlemen.

I completely agree with OMS that, as good practice, a live busbar inside an enclosure should be barriered.

I can understand your thinking when you say, "BS 7671 probably isn't the best approach either"

But, at what point does a distribution cabinet become part of the plant machinery, and not require testing under BS 7671?

It has been a big bone of contention as to whether these, (there are 12 if them) distribution cabinets receive a standard "Electrical Installation Condition Report' or not.

My feeling is that they should. I view these cabinets as distribution cabinets and feel they should be treated as any other.

I've also spoken to colleagues who believe these cabinets are part of the plant machinery and should be tested and inspected under equipment standards (PUWER).

I'd welcome any thoughts on this.
 11 October 2012 09:11 AM
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OMS

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Well, for what it's worth, you probably need to consider several aspects

1 - This cabinet (or cabinets) has a supply in and several supplies out which are controlled by circuit protective devices. So incoming supply (if not covered by say a test of a main switchboard outgoing supply tests) and certainly outgoing circuits to machinery need testing in acordance with BS 7671. This should include basisc refernces to UP ratings, access via a key or tool etc as well as the usual electrical inspection and tests

2 - You have a panel that almost certainly falls under the low voltage directive, may be switchgear and covered by BS EN 62208, BS EN 60947, BS EN 60439 and is probably also machinery under the machinery directive. PUWER would apply (as it almost always does) and here you would look at the process/procedure for entering this cabinet and the issue of bare busbars etc. CE marking would also be relevant

3 - There is an even broader duty also under EAWR derived from HASAWA etc - so a report on condition in more general terms will be required - and that should include the employers risk assessments etc

So it would appear that what you need is an EICR included as part of a broader report on the distribution cubicles which also needs client input in terms of existing policies and procedures and dialogue as to whether they need modification. Whether you just provide the EICR as input into a broader study by the client is, I guess, a matter of your appointment and the duties you have quoted for.

In any event, i would simply comment on the bare busbars without saying if it's compliant with a standard or not as part of your normal duty of care as an ordinary competent person. There is no problem raising the issue - you don't have to recommend a solution

Regards

OMS

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Failure is always an option
 11 October 2012 02:29 PM
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Jaymack

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Originally posted by: Jason555
The cabinet is metal and totally enclosed, approx 6ft by 2ft. It has a full size hinged door on the front which requires a cabinet key to open it, (I believe the key is called a Double Bit No.5 Key). Once opened all the breakers are exposed and so are all the busbars. The door can be opened whilst everything is live.
Should all the live busbars be covered/barrier/guarded or is this acceptable as using the double bit No.5 key constitutes "access only by a competent person"?

I wouldn't be concerned, since the cover can only be opened with the use of a tool. You could stick a label on "Isolate elsewhere etc." but even this is not required for access by a supposedly competent person.

Regards
 11 October 2012 09:15 PM
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Jason555

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Joined: 17 January 2011

Thanks very much for your advice gentlemen.
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