Is ppe needed ?

[jghrist]

If the label is from the results of an arc flash analysis then yes, it is the hazard at the working distance used for the calculation (Should also be on label) and is independent of the task being done or if doors/covers are removed or installed. Always the same, not task based like the tables.

This is true if there is an arc flash hazard. The question is: does operating the circuit breaker with closed doors create an arc flash hazard? This is controversial. Article 100 of NFPA 70E defines Arc Flash Hazard as

A dangerous condition associated with the possible release of energy caused by an electric arc.

Information Note No. 1 says that

Under normal operating conditions, enclosed energized equipment that has been properly installed and maintained is not likely to pose an arc flash hazard.

Informational Note No. 2 references the task tables for examples of activities that could pose an arc flash hazard.

Considering both informational notes, and the fact that the task table shows opening the breaker as Cat 0, IMHO, if the equipment has been properly maintained, Cat 0 PPE is adequate for operating a LV breaker behind closed doors.

 

[zog]

This is true if there is an arc flash hazard. The question is: does operating the circuit breaker with closed doors create an arc flash hazard? This is controversial. Article 100 of NFPA 70E defines Arc Flash Hazard as Information Note No. 1 says that Informational Note No. 2 references the task tables for examples of activities that could pose an arc flash hazard.

Considering both informational notes, and the fact that the task table shows opening the breaker as Cat 0, IMHO, if the equipment has been properly maintained, Cat 0 PPE is adequate for operating a LV breaker behind closed doors.

Define properly installed and maintained? Would you say a saety related system at a nuclear power plant has thier equipment properly installed and maintained? I sure would, and I also was just involved in the clean up of a breaker failure that blew the doors of the switchgear. This verbage is going to cause problems because many think thier switchgear is properly maintained when if fact it is very rare.

And the 70E also says to look at the task tables for examples of tasks that can pose an arc flash hazard.

I will never be convinced that there is no arc flash hazard operating a breaker because I get calls every single week to repair or replace breakers and switchgear that has failed from an arc flash event, way to common to see doors fail to bet my life on it.

 

[puckman]

Just a point of view from a few electricians.
At our place the motor control centers are never maintained in any way. Doors either have 1 screw to keep most doors closed or none. They have not been cleaned in atleast 5years that i can track down to.
Does the doors being closed mitagate being in an arc flash boundariy ? Does the working distance 18" on the bucket meam with doors open only ?
Is it a fact you can't use the tables once you have a arc flash analysis ?