eP Joule Rating

[Anonymous user]

What is the difference between eP Joule Rating and Surge energy rating (rated in joules)?

Thanks

[Anonymous user · Accepted solution]

Thanks Mike.

So it's really just a 'comparison' listing.
Is my understanding correct that the 'redirection' only works if the suppressor is plugged into a grounded outlet?

Also,
Are all APC suppressors UL 1449 compliant and minimum of 800 joule (comparative - eP) rated?

[Anonymous user]

paullr,

APC uses the eP Joule Rating because we do not simply 'absorb' the surge like some other surge products might. Our products are designed to redirect the surge back to ground instead of absorbing it and incorporate a let through voltage, which is the maximum transient voltage the attached equipment will be subjected to above the normal RMS voltage. Any remaining voltage is redirected to ground.

I believe the reason we even list the eP rating is for comparison with our competitors products. If we just listed the standard Joule rating, it would in most cases be lower than the competitors, because we aren't relying on absorbing the impact with a MOV, we're redirecting excessive voltage away from your equipment and safely back to ground.

From my understanding, we come up with the eP Joule rating by performing real world tests with both our equipment and the competitors. Based on these results, we can see how many Joules of absorbtion our units are equivalent to.

-Mike

[Anonymous user · Accepted solution]

paullr,

Correct, grounded outlets are needed for these products to function correctly, which is why we have the Site Wiring Fault (SWF) indicator to notify you if there is a problem with the outlet that it is plugged into.

And yes, all APC Surge devices are UL1449 compliant. Some devices do have a lower eP joule rating, such as the P6B (yeah, it's an $8 surge strip). But most, even some that are only a couple dollars more, have ratings much higher than 800 Joules eP.

-Mike

[Anonymous user]

Helpful thread. As it happens I did a live chat today and the rep. said it would still work without being grounded. Apparently that's a bit misleading as no explanation was offered as to what the consequences might be. Maybe the instructions would have addressed this. Thanks to this thread I see I have to add a grounding wire.