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#163659 - 05/13/07 08:11 PM What constitutes working live at 600v
frank Offline

Registered: 05/29/01
Posts: 361
Loc: windsor ontario canada
If your working on a combination motor starter that has the exposed disco open is it considered live work?
IS live testing concentered working live work?
Is working on or around cycling equipment considered live work?
What is considered a high energy circuit?
I guess im trying to find out when PPE becomes necessary.Any links you may have would be greatly appreciated.Seems everyone has differing opinions.

Arc Flash PPE Clothing, LOTO & Insulated Tools
#163668 - 05/14/07 07:06 AM Re: What constitutes working live at 600v [Re: frank]
Zog Offline

Registered: 09/13/05
Posts: 116
Loc: Charlotte, NC
"If your working on a combination motor starter that has the exposed disco open is it considered live work?"

Depends on what you are doing

"IS live testing concentered working live work?"

That is an exception to the EEWP requirement, so no it is not. However you still need to wear the proper PPE.

"Is working on or around cycling equipment considered live work?"

Again, depends on what you are doing. Any interaction with the equipemt requires PPE for arc flash protection even if live parts are not exposed.

"What is considered a high energy circuit?"

Thats a pretty vauge question. The IEEE 1584 addresses arc flash hazards for 208V systems if the suppling transformer is > 125kVA, thats where the arc is self sustaining and relies on a protective device to clear it.

"I guess im trying to find out when PPE becomes necessary.Any links you may have would be greatly appreciated."

You will find PPE necessary for most tasks, typoically the arc flash hazard on 480V systems is greater than that on 13,800V systems. You can find arc flash info at

"Seems everyone has differing opinions."

Who is everyone? Either you are in compliance with the 70E or you are not, be careful who you listen to. Sounds like you need some training on the topic.I notice you are in Windsor, there is a 70E compliance course in the Detroit area every month, next one is June 7th-8th.
MV/HV Testing Specialist, "BKRMAN"

#163669 - 05/14/07 07:12 AM Re: What constitutes working live at 600v [Re: frank]
renosteinke Offline
Cat Servant

Registered: 01/22/05
Posts: 5305
Loc: Blue Collar Country
I've seen the simple measurement of hot/not hot be argued either way; this is because the starters typically have flash shields installed that still allow for the use of meter probes.

Going by the book, it seems to say PPE is required when you verify 'off.'

In short, we've all been taught wrong, and have been doing it wrong, for all our lives.

Cycling equipment, with the covers on the equipment, is not considered live work. There ARE lock-out / tag-out issues, though.

High energy? Your guess is as good as mine!

Now ... rule book aside ... there are different levels of risk. Higher voltage does greatly increase the risk of flash-over and arcing, as well as make it much easier to exceed the 'let go' threshold. You mention 600 volt work, which suggests this is not your typical industrial setting.

There are different (somewhat relaxed) rules for PoCo work, than for ordinary electrician work. I suspect this is more an accident of differing codes, rather than a deliberate decision of the code panels.

#163697 - 05/14/07 09:30 PM Re: What constitutes working live at 600v [Re: renosteinke]
OSHA Professor Offline

Registered: 12/06/02
Posts: 50
Loc: Chicago
OSHA’s Electrical Safety related Work Practice Standards 29 CFR 1910.331-335 specifically 333a1 states that “Live parts to which an employee may be exposed shall be deenergized before the employee works on or near them”.
This is essentially the same verbiage as NFPA 70E Article 130.1
The key words are, on or near them. When an electrical enclosure is opened whereby exposing live parts then that requires PPE until the circuit is deenergized, locked and tagged out, and verified for “absence of voltage” with test equipment. Only when this has been completed can the PPE be removed.

Somehow all that got watered down to simply working live, and with a very nebulous definition of same and even more vagueness of the required PPE required. A look at the NFPA 70E hazard risk category classification tables require PPE for both burn and electrocution protection whenever any enclosure dead front cover is removed to expose energized electrical parts.
The level of burn protection required is NOT dependent upon voltage but rather the available level of fault current. In short the magnitude of the arc blast/arc flash is energy related not voltage related. Factors which dictate the available level of fault current are the separately derived system/transformer size, feeder/circuit/conductor impedances between the transformer and the point of potential exposure. It is true as mentioned in another post that the fault current levels are generally greatest at 480v. The closer you are working to the transformer and the larger the transformer the higher the available energy and the greater the level of PPE. I have a simple saying I use in the classroom. The bigger the equipment the greater the hazard (and consequently the higher level of PPE required). IEEE 1584 is OK for engineers but unless you are a EE don’t even look at that standard, it will make your hair fall out and eyes cross. The tables in 70E are much better guide. They don’t include every conceivable task but you can find a task listed in the tables close to what you are doing and have a decent PPE guide.

Cycling equipment with covers on the electrical enclosures poses essentially no electrical hazard exposure although the cycling of high energy/current equipment by say flipping a 200a breaker on and off where a breaker could blow apart for various reasons (breaker failure, improper short circuit rating etc.) it would be wise to at least have on FR coveralls, leather glove, safety glasses equivalent to a hazard risk category one in the 70E tables. Additionally the cycling of equipment where a mechanical hazard exposure exists because a barrier guard is missing or non existent would require lock out under another standard for protection of the mechanical exposures although this should have already been addressed through machine and machinery guarding including belts, pulleys, gears, sprockets, moving machinery, points of operation etc. This is not an electrical hazard exposure issue but a machine guarding and machinery lock out issue as was also mentioned in another post. There is another OSHA Lockout/Tagout standard for these exposures. 29CFR 1910.147

Finally, I’d like to mention that I have conducted many fatality investigations. One investigation was where someone was working in a 480v disconnect switch, in the off position with only the line terminals energized, additionally a barrier guard over the line terminals and the person was burned to death in an arc blast. Was it switch failure, uninsulated tool or hardware dropped across the energized terminals? Well never know for sure. The indisputable facts of the case are these: There were energized/live parts inside the disconnect switch (not deenergized and locked out), the disconnect cover was open, the electrician was doing something inside the switch, tools were being used to some extent, none of the electricians tools were rated (insulated), the electrician was wearing synthetic blend clothing, this was in a power plant, and the deceased victim had a wife and several children.

80% of the fatalities among qualified electrical workers are due to arc blast/arc flash. Please be careful out there!

#163703 - 05/15/07 06:53 AM Re: What constitutes working live at 600v [Re: frank]
frank Offline

Registered: 05/29/01
Posts: 361
Loc: windsor ontario canada
I should give you a little back round
I'm a 38yr old industrial electrician here in Windsor Ontario Canada working in a large medical Building for the last 17yrs.
Typical work involves installing maintaining and troubleshooting building automation systems such as Johnson controls Metasys,Train Tracer Summit and Swiss Logic.
Working on controls in and around cycling 600v equipment is frequent and required.

Canada and specifically Ontario is far behind the U.S. in electrical safety.In 2004 the government introduced a new bill C45 that requires employers to take reasonable care and precaution in the life safety of employees.Criminal charges of up to life in prison and fines up to 100000 can be levied against managers and supervisors who do not practice "DUE DILIGENCE".
Canada has nothing like NFPA 70e leaving employers and employees in a state of limbo as to exactly what constitutes due diligence
In reaction to this some companies have adopted 70e an some have not.
It has come to our attention that 70e has now been given Legislative power until Canada produces it's own regulation.CSA Z64 will be closely modeled after 70e.The Canadian electrical code now refers to 70e but sadly the province of Ontario has yet to adopt this new code.

Edited by frank (05/15/07 07:04 AM)

#163706 - 05/15/07 08:58 AM Re: What constitutes working live at 600v [Re: frank]
mikesh Offline

Registered: 06/07/06
Posts: 614
Loc: Victoria, BC, Canada
what does 2-306 say in Onterrible? What notes in Apendix B are attached. This is what gives 70E legislative force. It is still vague and the Canadian standard is probably not comming before 2009.

#163753 - 05/16/07 07:38 AM Re: What constitutes working live at 600v [Re: mikesh]
frank Offline

Registered: 05/29/01
Posts: 361
Loc: windsor ontario canada
2-306 Maintenance of Live Equipment
No one shall work on any live equipment unless
protected by approved insulated or insulating devices such as tongs,boots,mats ect,which shall always be maintained in proper condition for use
There is no reference to any appendixes including B.This is from the 2002 code as the new code has not been adopted yet.
There is no wording in any code book that states 70e as having legislative power but the courts have allowed it as proof of due diligence in past cases making it a precedent.
The Institute of and Electrical and Electronic Engineers as well as the Safety Education Association of Ontario which is provincially funded through WSIB both state acceptence of 70e.
Who works live 600v anyway?Other than changing breakers and wiring splitter lugs i don't see what can be done live.
Its working in and around the starters on devices such as current coils and troubleshooting like live testing.That becomes the real issue for me.I have talked to inspection and they say there is no law or code in ontario other than 2-306.We are on our own plain and simple.
The employer could care less how vague 70e as is the only CYA option currently in the game.
thanks again

Edited by frank (05/16/07 07:44 AM)


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