1 members (Scott35),
235
guests, and
27
robots. |
Key:
Admin,
Global Mod,
Mod
|
|
|
Joined: Aug 2005
Posts: 4
OP
New Member
|
I need to know if my training is lacking or if a concern from a manager has no merit. The manager is insisting that 30 cal flash gear is needed to reset a tripped 3000A 480 VAC main breaker. The breaker and all the gear around it is fully enclosed. The Approach is 26.5 ft and limited is 3.6 feet. Am I wrong to assume that these barriers only apply with the covers open. I definitely will need to review 70E to set myself or the manager straight. I appreciate his zeal to keep us safe but this seems extreme. What do you all think?
|
|
|
|
Joined: Dec 2000
Posts: 4,294
Member
|
If the covers are all on, no PPE is required, much less a 30 cal suit. Ask the manager if he puts on flash gear to reset one of his breakers at home
|
|
|
|
Joined: Apr 2002
Posts: 7,382 Likes: 7
Member
|
Is there any concerns over what tripped the 3000 amp main?
Hopefully it was the GF
John
|
|
|
|
Joined: Jul 2001
Posts: 599
Member
|
Am I wrong to assume that these barriers only apply with the covers open. Appropriate PPE is always required, regardless of covers being present or absent. closed covers mitigate any possible shock incident, and they probably do help in the prevention of an AF occurrence, but the do nothing to lower the amount of incident energy. While I might judge the 'normal operation' of a 3000A breaker between open and closed as having a low risk of an AF occurring, there is no way I would 'reset' a tripped breaker without PPE based on the available incident energy.
|
|
|
|
Joined: Jul 2001
Posts: 599
Member
|
If the covers are all on, no PPE is required, much less a 30 cal suit. The PPE requirements need to be part of the company's Electrical Safe Work Practice program.
|
|
|
|
Joined: Jul 2004
Posts: 787
Member
|
The PPE requirements need to be part of the company's Electrical Safe Work Practice program. So the outside consultant with a vested interest in separating you from your money, will specify the most conservative interpretation of the 70E rules in order to validate their cost to the company. Meanwhile you will need PPE to plug in a vacuum cleaner in the office spaces.
|
|
|
|
Joined: Dec 2000
Posts: 4,294
Member
|
Bob, Refer the manager to Table 130.7(C)(15)(a) of 70E, available @ http://www.depts.ttu.edu/opmanual/OP60.14B.pdfIt lists the Hazard/Risk Category Classifications. Panelboards or Switchboards Rated >240 V and up to 600 V (with molded case or insulated case breakers)
CB or fused switch operation with covers on
Hazard Risk = 0 ______________________________________________________
600 V Class Switchgear (with power circuit breakers or fused switches)
CB or fused switch operation with covers on
Hazard Risk = 0
|
|
|
|
Joined: Jul 2001
Posts: 599
Member
|
So the outside consultant with a vested interest in separating you from your money, will specify the most conservative interpretation of the 70E rules in order to validate their cost to the company. Meanwhile you will need PPE to plug in a vacuum cleaner in the office spaces. If the people doing your analysis are the same ones that are selling you your PPE, you probably have a point. My point is; it is not a requirement of NFPA70E that you employ any more PPE than is necessary to perform the task. The typical AF study says how bad things could be (the hazard), not how likely they are to occur(the risk). 70E clearly says that the risk must be analyzed as well as the danger. The is partly why their 'task tables' result in a Hazard Risk Category instead of simply cal/cm^2.
|
|
|
|
Joined: Jul 2001
Posts: 599
Member
|
Bob, Refer the manager to Table 130.7(C)(15)(a) of 70E.... And make sure that all of the conditions (fault current, opening times, and regular maintenance) are met.
|
|
|
|
Joined: Jul 2004
Posts: 9,931 Likes: 34
Member
|
This is like most things "safety" related. If it is worth doing, it is worth over doing.
You only have to look ad lead paint and asbestos abatement this in action. Someone dug up some sewer pipe here in a road expansion project that *might* have had some asbestos in it and instead of some reasonable response, they shut down the project for months, hauled about 100 yards of dirt for "safe disposal" and treated the pipe like it was plutonium. Everyone involved was punished in some way and the contractor went bankrupt. An overpass took years and many extra millions to complete.
Greg Fretwell
|
|
|
Posts: 57
Joined: August 2003
|
|
|
|