Fuse blew in UPS power cable - tripping the circuit. Causes?

[Anonymous user]

Hello,

I have a Smart UPS 1500 (SMT1500I) that protects two servers/a switch/gateway router/WAP and PBX. It is not in any way overloaded (usage is sitting around 15%) and has a long run time. It has been in service for about 4 months with no issues in that time and has protected the hardware during several outages and overvoltages.

On Weds evening Powerchute notified me that there had been a loss of power at the site location and then 15 minutes later a shutdown of the two servers was initiated. This was fine as that's what I wanted it to do. Come the next morning everything was still off so I assumed there was a prolonged outage at the site. On investigation by the client, it appears that the main board trip switch for the comms room had been tripped - no other power in the building was off and there had been no power outage. Further investigation showed that the fuse had blown in the cable from the wall socket to the UPS (I am in the UK) and only after replacement and resetting the trip did the UPS start to charge up.

Everything is now working fine, but I am curious as to the reason for the blown fuse in the power cable? Could it be just "one of those things"?

[BillP]

i would make sure that none of your attached equipment has a short or similar.

also, I know this UPS has a C13 input connection? what type of power cord is this? (forgive me as I am based in NAM and I am only really familiar with C13-C14 for 230v or C13 to NEMA 5-15 for 120v domestic applications here).

[Anonymous user · Accepted solution]

Thanks for your reply.

Yes, it is a C13/C14 type system: http://en.wikipedia.org/wiki/IEC_60320#C13.2FC14_coupler - C14 (male) on rear of UPS, C13 (female) at the one end of the cable supplied by APC. At the wall socket, the cable has a UK plug (BS1363) incorporating a fuse (seems we're about the only ones to do this) - in this case the plug contained a 10amp fuse (as supplied by APC), which apparently blew.

I haven't seen this myself as I am remote from the system - the client stated this is what happened and the UPS only started to re-charge when she swapped the C13 > BS1363 cable for another identical one (we have plenty around as PCs use them as well).

It is all very odd... I can only think, like you, that something shorted out, but everything is back up working again without issue (all the hardware is 4 months old).