Panel Safety Questions

We are buying some new equipment and one of the things we asked for in the electrical control panel was for all devices to be touch safe like recessed terminals and terminal guards,etc.

The OEM Sent us back a cost of $4,900 to make it a CAT 3 panel so I assume category 3 but I am not really sure what this means but the cost seems excessive when it's the way you should be designing panels anyway IMHO.

Just looking for tips,advice and thoughts on this situation.

Tim,

you have two issues here.

#1 touch safe terminals, thats pretty standard on most things.

#2 CAT 3 rating. this is an electrical arc flash rating (NFPA70E).
the arc flash rating determines how much PPE is required. what we try to do is isolate the 480, 240, 120, and 24 volt circuitry. then we can get into the plc controls without much fuss.
our panels in the plant require CAT2 PPE.
protective clothes, gloves, hood.

hope this helps.
regards,
james

shift focus

Finger safe is an old-school strategy to protect humans working in known energized enclosures.

NFPA 70E says, "Do NOT work in energized enclosures". PERIOD

You should have communication ports for programmers.

If persons must open enclosures for live diagnostics, they must have A: written reasons that this can not be done de-energized, and if approved by management, B: they must have PPE rated for the calories.

You can segregate all of the 480 into one enclosure, and have all of the 24vdc in another enclosure to limit calorie exposure.

Tim Ganz said:

We are buying some new equipment and one of the things we asked for in the electrical control panel was for all devices to be touch safe like recessed terminals and terminal guards,etc.

The OEM Sent us back a cost of $4,900 to make it a CAT 3 panel so I assume category 3 but I am not really sure what this means but the cost seems excessive when it's the way you should be designing panels anyway IMHO.

Just looking for tips,advice and thoughts on this situation.

Click to expand...

Look at it this way, $5 grand is a lot cheaper than replacing a tech who expires due to unsafe conditions.

But there is something to be said about the "natural selection" of the "weak minded" & careless.

They need to explain in detail what they mean by "CAT 3" instead of making you guess.

An NFPA 70E arc-flash hazard "Category" refers to the amount of danger posed by the conductors and therefore the type of PPE you need to wear to work on them.

Category 3 is the second-to-highest: it's for when you're removing bolted covers to work on 600V live conductors.

I think you'll agree that this is the opposite of finger-safe !

I agree you need more clarification of what they meant. "Cat 3" could also mean SIL (Safety Integrity Level) category 3 (not really an official term, but it gets used a lot), although that too would have nothing to do with "finger safe" terminals.

Add me to the group that say you need clarification. Cat 3 in my world is short for category 3 safety.

RussB said:

Look at it this way, $5 grand is a lot cheaper than replacing a tech who expires due to unsafe conditions.

But there is something to be said about the "natural selection" of the "weak minded" & careless.

Click to expand...