Arc flash ppe for traffic signals

[DANIEL LAWLOR]

Hi Everyone:

Would anyone know what the required or recommended PPE is for arc flash protection when working in front of a traffic signal control cabinet based on either NFPA 70E or CSA Z462? Is anyone aware of an arc flash analysis having been done for this application (traffic signal control cabinets)?

Some of the details are:

- feed is 120 VAC, single phase, usually from overhead hydro wires
- feeds are unmetered in our municipality
- breaker is rated at 30 amps, 10 kA interrupting capacity
- the incoming feed wires terminate behind a plexiglass shield
- exposed 120 vac terminal strips are present for feeding traffic signal
lights (load side wiring) when the cabinet door is open

I'm more concerned about the IMSA traffic guys who program the signal timer
which sits on the shelf above the terminal strip than the electricians who work on the wiring.

Thanks,

Dan.

 

[RoberteFuhr]

Most likely the Arc Flash Energy is very low. IEEE 1584 does not have equations to determine single phase arc flash energies. However, you could treat it a three phase source. IEEE 1584 has an exception that allows states the HRC can be considered to be 0 if the equipment is rated 240 VAC or less and is fed by a transformer less than 125 kVA. I would also recommend that your staff wear HRC 2 clothing when working around electrical panels.

 

[SG-1]

Pretty much anything outside is CAT IV due to lightning induced transients.

http://support.fluke.com/find-sales/Download/Asset/2071940_A_w.pdf

 

[jim dungar]

However, you could treat it a three phase source.

Why??

Why not assume a maximum of HRC=1 based on the task tables for <240V equipment?

 

[weressl]

Pretty much anything outside is CAT IV due to lightning induced transients.

http://support.fluke.com/find-sales/Download/Asset/2071940_A_w.pdf

Could you point out where NFPA 70E requires THAT to be considered?:roll:

 

[SG-1]

Could you point out where NFPA 70E requires THAT to be considered?:roll:

You are of course correct.

Obviously my blondness asserting itself. :roll:

 

[weressl]

You are of course correct.

Obviously my blondness asserting itself. :roll:

Funnnny:grin::grin::grin:

It occurs to me that many babies born with blond hair that turns dark in adolescence.


But all of us turn really blond for old age...........:roll: OKOKOK it is WHITE.....but it is close?!

 

[SG-1]

Funnnny:grin::grin::grin:

It occurs to me that many babies born with blond hair that turns dark in adolescence.


But all of us turn really blond for old age...........:roll: OKOKOK it is WHITE.....but it is close?!

I think that is called " beach blonde ", or was that " bleach blonde" ???

 

[DANIEL LAWLOR]

Thanks very much.

 

[GonzaloGomez]

Caltrans PPE

Caltrans PPE

We have been looking into this subject for a while and are in the final stages of implementation.

We are probably going to require a minimum of HRC 0 (or equal) for tasks like changing timing or configuring the controller.

For other tasks in the cabinet, we are going to require a minimum of HRC 1 (or equal), but the electricians in the field are going to be protected to HRC 2*. We do not want our electricians to have too many choices for PPE (less confusion), and at any time, they may be exposed to 480 VAC (lighting circuits).

GG