IET logo
 
IET
Decrease font size
Increase font size
Topic Title: Permit to Work Question
Topic Summary:
Created On: 08 October 2013 04:40 PM
Status: Post and Reply
Linear : Threading : Single : Branch
Search Topic Search Topic
Topic Tools Topic Tools
View similar topics View similar topics
View topic in raw text format. Print this topic.
 08 October 2013 04:40 PM
User is offline View Users Profile Print this message


Avatar for timothyboler                                      .
timothyboler

Posts: 230
Joined: 25 July 2008

Hi all,

Been involved in a discussion of our permit to work system in the office as there's confusing as to exactly the scope of the document.

Firstly HSE Guidance 85 states that:

"An electrical permit to work is primarily a statement that a circuit or item of equipment is safe to work on - it has been isolated and, where appropriate, earthed. You must never issue an electrical permit-to-work for work on equipment that is still live or to authorise live work"

However it's being argued that the act of racking out circuit breakers or removing MCC drawer etc on LV and HV switchboards is in itself a hazardous activity and should be controlled by the permit. The above would assume that the breaker is racked out and locked in the off position etc BEFORE the permit is issued.

How is this normally managed? By having two permits or simply omitting permits for for racking operations. The operators of the switchgear have to be competent in order to do this work so I'm arguing that it's not required. Or is the HSE guidance not 100% correct and that a permit could be issued before isolation and include the racking operation? Would be interested in your thoughts.

Thanks, Tim.

-------------------------
Everyone loves a fireman - but hates the fire inspector.
 08 October 2013 05:39 PM
User is offline View Users Profile Print this message



Jaymack

Posts: 4647
Joined: 07 April 2004

I would think, that it is not necessary to issue permits for work that is considered routine, for a competent person.

As a one time factory and project/commissioning engineer; and SAP with the Scottish Hydro Electric Board, I am accustomed to writing, issuing and working to Permit to Work schemes, for all disciplines.

You will find that some or probably most MV and HV breakers nowadays, have a means of closing the breaker onto the circuit earthing position when racked out. Bucket compartments on LV and MV MCCs are easily switched off and are probably interlocked, such that they can only be opened or withdrawn in the OFF position. Each situation has to be carefully analysed however, and safeguards made as far as possible to avoid isolating the wrong equipment, and even locking "OFF" equipment when in the "ON" position!

Regards
 08 October 2013 06:00 PM
User is offline View Users Profile Print this message



Fm

Posts: 679
Joined: 24 August 2011

In my world the senior authorised person will issue a permit after he/she has carried out an isolation.
We issue permit to enter into switchroom for all staff.
We log switching in the switchroom log
We iissue permit to test for testing, so that the process has been thought about before some dafty applies 500volts to an instrument for example
 08 October 2013 07:55 PM
User is offline View Users Profile Print this message



MickeyB

Posts: 181
Joined: 18 January 2003

The 1st step I would advise is to agree who's safety rules are in use..... and what do the rules say about live working etc...
The definition of live working (including testing)..... adopted by many is that live working is the removal/ testing of a device that is/ was energized prior to removal eg. a fuse or tap off box and where IP2X is not provided.

If you are working with either of the above you are probably live working and a Sanction to Work (on or Adjacent to) Live (Conductors) should be issued.

Live testing falls under the same category, although IP2X is usually available for most testing scenarios and therefore a Sanction for live working is not required.

A Standing Instruction (Method Statement with Risk Assessment) may be appropriate for some repetitive tasks to avoid the issue of a Sanction to Work Live every time..... this would need to be authorised by the Authorising Engineer

Racking in/ out of a device that is designed to be operated 'live' does not necessarily require a sanction to work live provided no conductors are exposed, less than IP2X presented when racking in/ out. Typically shutters of some kind will maintain the IP2X level of protection and the spouts or male elements will be concealed when moving etc...

Adding a new tap off box to a live bus bar..... Live working.
Inserting a BS88 fuse carrier into a fuseboard..... Live working.
 09 October 2013 06:21 AM
User is offline View Users Profile Print this message



MrP

Posts: 843
Joined: 24 March 2006

Hi Timothy
If you are racking in breakers a permit to work is iMHO essential to safe working practice as others have stated the procedure of racking a braker in or out is easily undertaken this to me would sound the alarm bells
A permit to work clearly identifies a clear line of authority, procedure and risks to the safe energisation of a system. This includes the actual task and the consequences of the action and is a fundamental cornerstone to safe energisation of electrical systems. If it can go wrong it will go wrong, a safe system of works mitigates that risk
I personally would not let a contracter who did not implement a safe systems of work operate on my sites
It is part of the procedure of design construction I&T
 09 October 2013 06:31 AM
User is offline View Users Profile Print this message



MrP

Posts: 843
Joined: 24 March 2006

Sorry inadvertently pressed the send button using a smart phone requires a smart person
The last line should read
For me it is part of the procedure of design, construction, I&T and energisation process you can't have one without the others a safe systems of work (permit) is essential

MrP in Oman
 09 October 2013 03:18 PM
User is offline View Users Profile Print this message


Avatar for timothyboler                                      .
timothyboler

Posts: 230
Joined: 25 July 2008

Thanks for your comments. From the above responses it seems like issuing a permit for enclosed racking operations where no live parts are exposed then a permit isn't necessary (assuming the switchgear operator is competent of course) as this is a routine operation. Where LV boards require racking, removing fuses etc. exposing live parts then a live working permit should be issued. That would make sense to me.

Cheers, Tim

-------------------------
Everyone loves a fireman - but hates the fire inspector.
 09 October 2013 06:51 PM
User is offline View Users Profile Print this message



Fm

Posts: 679
Joined: 24 August 2011

As a senior authorised person under our electrical safety rules, i dont need to issue myself a permit.
I do need the relevant ms/ra for the work, but the authorising engineer has deemed me to be competent.
 09 October 2013 07:18 PM
User is offline View Users Profile Print this message



Jaymack

Posts: 4647
Joined: 07 April 2004

Activities deemed to be carried out by a competent person, albeit that they are also trained on a general employee induction course, should not require a permit IMO, they should also sign to the effect that they have been instructed, with periodic refresher courses.

Each industry requires differing methods of tackling such safety issues, there could be a case to raise permits for switching under instructions, either directly or by telephone, and perhaps with an accompanying party, for strategic industries such as electricity distribution, hospitals and industry in general etc.. Large projects where there are many disciplines involved, probably require a marshalling co-ordinator in each substation or switchroom. One of the big pitfalls I found was with mental aberration. A committee should be formed from experienced personnel, to draw up such documented procedures, for any industry and location.

Regards
 11 October 2013 10:19 AM
User is offline View Users Profile Print this message


Avatar for timothyboler                                      .
timothyboler

Posts: 230
Joined: 25 July 2008

I'm going to back-track a bit on what I said before after reading the comments

I can agree that isolation of an MCB or MCCB in an enclosed switchboard is a routine operation and as long as no live parts are exposed no need for a PTW.

However image racking out a 5000A LV ACB on a 10 year old switchboard. Or swapping out a motor starter drawer. Even if no live parts are exposed with shutters and full enclosures there is a risk of equipment fault and recommendation would be to take extra precautions (extra PPE for example). So in this situation I would suggest that even with a competent operator a PTW would be required. As others have said the act of racking the breaker out can be more hazardous that the operation of working on dead conductors.

Does anyone have an example permit for racking operations? Would you include racking scope in the standard Electrical PTW or have two separate documents?

Thanks Tim.

-------------------------
Everyone loves a fireman - but hates the fire inspector.
 11 October 2013 01:55 PM
User is offline View Users Profile Print this message



MickeyB

Posts: 181
Joined: 18 January 2003

if you found yourself in that sort of situation you would more than likely have an operational restriction placed on the equipment which may restrict to dead switching only or other restrictions on use. if the equipment cannot be confirmed safe to switch you do not switch. you have to know what you are switching before you switch. if not don't switch.
 16 October 2013 02:33 PM
User is offline View Users Profile Print this message



rogerbrand

Posts: 26
Joined: 22 March 2002

I fully support the statement taken from HSG85 that you quote in your original posting.

A Permit to Work (PTW) is a formal safety document which states, in effect, that electrical equipment once live is now safe to touch with your bare hands. This means it has been identified, isolated from all sources of electrical energy and proved dead.

In my experience there is a lot of confusion about the correct application of a PTW ranging from its use as a general job instruction through to authority to work on live equipment. Other safety documentation is available to deal with these situations,

Taking the example quoted, racking out a healthy circuit breaker does not require a PTW. If the condition of the circuit breaker is suspect for any reason it will need to be isolated (and earthed if HV) upstream and a PTW issued before anyone attempts to operate or work on the suspect breaker.

Whether the work is routine or not isn't a factor. Competence most certainly is.

Roger
 16 October 2013 06:27 PM
User is offline View Users Profile Print this message


Avatar for OMS.
OMS

Posts: 19688
Joined: 23 March 2004

Is the point here that the switching operation to achieve that safe system of work isolation is also covered by the permit - how else do you control the re energising, You can't have a live permit that doesn't encompass the means or method of achieveing the isolation independant of the task.

Eg - the permit would need to define that CB 1X is tripped and racked to earth and locked out (possibly with multiple keys beloging to multiple signatories of the PTW) before undertaking maintenance on Feeder Y or plant Z - that's the first task isn't it ? - the last task being the confirmation that work is ceased, the plant ready to be re energised and then the switching to "on" proceeds with removal of the lock outs etc

Regards

OMS

-------------------------
Failure is always an option
 29 April 2014 10:38 PM
User is offline View Users Profile Print this message


Avatar for FizzleBang.
FizzleBang

Posts: 936
Joined: 05 January 2007

I work for a utilities company at a large waste Water Treatment Works and carry the title of Responsible Person for the site while on shift.

It's one of my jobs to issue Access Certs and Permits to Work.

An access cert is issued to all visitors who are undertaking work on site. Where the job involves a particular hazard (i.e. electrocution) there will also be a Permit to Work issued.

The three signatories are the Responsible Person, the Person Coordinating the Work (usually a company Field Service Engineer) and the Contractor.

Where electrical work is being undertaken the site FSE will also issue an Electrical Safety Notice which is signed by the Contractor. It is this document that specifies the isolation procedure.

In the PTW I will merely identify Electrocution as a hazard and give Safe Isolation as control measure. How that is done is between the FSE and the contractor.

Much of the time the FSE will have isolated prior to the contractor arriving and will go over the isolation with the contractor before work starts.

So, for example, when we recently had a big Donkin Blower constantly tripping the HV, contractors came to Baker test it the 6.6kV motor.

I issued the paper work having already locked off the LV panel (removal from service). The HV isolation was outside my realm .

There is now a system of internal Work Authorization being introduced whereby our own Sparks will need to have paperwork issued prior to starting work. That's more about those of us running the place know what is being done and by whom and not about overseeing isolations etc.

-------------------------
"I learned very early the difference between knowing
the name of something and knowing something". - Richard P. Feynman
 29 April 2014 11:16 PM
User is offline View Users Profile Print this message



timothyarnold

Posts: 55
Joined: 12 January 2012

I had the same conversation with the E.O.N trainers last year. In E.O.N a switching schedule is produced to achieve isolation including the necessary safety locks and isolation notices. This activity is completed and then a PTW is issued to the contractor(s) competing the work. The bullet test is can you put your hand in the equipment and not get electrocuted. Sanctions for Test are used for testing whilst live.

PTW in some organisations is to identify and potentially (!) hazardous activities such as hot works, excavation, roof etc and these are issued before the work is started. IMHO his could be achieved by risk and method statements being approved and managed by a single individual
 30 April 2014 08:02 AM
User is offline View Users Profile Print this message


Avatar for FizzleBang.
FizzleBang

Posts: 936
Joined: 05 January 2007

Originally posted by: timothyarnold





PTW in some organisations is to identify and potentially (!) hazardous activities such as hot works, excavation, roof etc and these are issued before the work is started. IMHO his could be achieved by risk and method statements being approved and managed by a single individual


This is the way it works with my employer.

It's an extremely contentious issue at the moment! Just what are we trying to achieve?

As RP for the whole site my own concern is that we don't get contractors rocking up and isolating stuff will-nilly. So the PTW will identify which isolations are required but not how.
If HV is being switched or BUS couplers operated it will always be in the presence of company engineer(s).
And I will also have my lock(s) on panel(s) somewhere in the isolation process to ensure plant cant be re-energised without my knowledge.

As you say, the main premise of the PTW is to identify particular hazards (changeable atmosphere, bio-hazard and the ridiculously ever present "slips trips and falls"!).
The PTW also makes the RAMS part of the conditions of work. I'm not expected to be a Competent Person in respect of reviewing a contractor's RAMS, however, the PCW is. I am expected to read the RAMS and identify general hazards.

The PTW also has boxes where the permit can be renewed for a further 4 working days. These are signed by the RP and contractor at the beginning of each successive day.

It's become more of a muddle since the company's H&S dept. redesigned the whole Work Authorisation process

-------------------------
"I learned very early the difference between knowing
the name of something and knowing something". - Richard P. Feynman
 30 April 2014 09:07 AM
User is offline View Users Profile Print this message



timothyarnold

Posts: 55
Joined: 12 January 2012

Originally posted by: FizzleBang
It's become more of a muddle since the company's H&S dept. redesigned the whole Work Authorisation process


I think you've hit the nail on the head.

In our organisation we use "permits" for electrical isolation and these are written and issued before the work is started and this is really to ensure that we are controlling our contractors.

We use the permit to ensure that we fully understand which service(s) will be impacted and ensuring that we have received the necessary risk assessment and method statements.

I guess you could all this Work Authorisation Permit rather than PTW!
Statistics

See Also:



FuseTalk Standard Edition v3.2 - © 1999-2014 FuseTalk Inc. All rights reserved.