Cold Sequence Meter Disconnects for Fire Pumps

[JoeStillman]

So 40.01cal/cm² is unsafe but 39.99 is perfectly safe?
These must be customer specific break points, because NFPA 70E does not contain any color coding.

I have never found utility side primary fuses to make much different on my customer's service equipment arc flash values.

SKM sorts you into orange and red labels based on the PPE table you choose. It used to be impossible to find PPE rated for 40 Cal/cm², although that has changed. But the default table still breaks off at 40 Cal.

Your right, with a standard impedance transformer the AF energy isn't affected much by a line side fuse, but it you use a transformer with %Z in the 1.5 - 2.5 range you'll see a difference.

 

[JoeStillman]

As a general rule we fuse ours to 200% of the transformer.
We don’t do it to protect the customer.
We do it to protect the transformer. Over size a fuse to 300-600% and it tends to make the tops blow off them when something happens.

Says here those transformer fuses don't even know the fire pump is there...

 

[Hv&Lv]

Says here those transformer fuses don't even know the fire pump is there...
View attachment 2570906

Yep. Your right.
If all my voltages, kVA, fuse sizes, no existing loads, etc match the values in this sheet, it won’t see the 100 HP motor

 

[jim dungar]

SKM sorts you into orange and red labels based on the PPE table you choose. It used to be impossible to find PPE rated for 40 Cal/cm², although that has changed. But the default table still breaks off at 40 Cal.

SKM labels do not meet ANSI Z535 standard for labels. Their color coding is wrong and their verbiage is not sufficient.

But hey, compliance with NFPA 70E suggestions is up to the customer and their safety program.

 

[JoeStillman]

SKM labels do not meet ANSI Z535 standard for labels. Their color coding is wrong and their verbiage is not sufficient.

But hey, compliance with NFPA 70E suggestions is up to the customer and their safety program.

SKM Comes with about 120 different label templates. I think there are a few that comply with ANSI Z535.4. If it doesn't meet your interpretation, it lets you design your own label, right down to the RGB values of the colors. I've tweaked a few of them myself.

We use a weather-proof, vinyl, self-adhesive label with orange (Warning) and red (Danger) pre-printed at the top and project-specific info in the areas below. I've spent hours and hours getting it to comply with one client's requirements.

About 10 years ago 70E moved away from the classic PPE chart (Levels 0 - 4) but a lot of people still want that and SKM hasn't turned it off.