Safety Alert - APC Back UPS

Equipment affected: APC Back-UPS CS-650

Approximate age: Purchased on 4th Dec 2009

Where and how is it used? It is a UPS (Uninterruptible Power Supply ) which protects the BNCS, desktop and Radioman PCs

Who uses it? BBC Local Radio engineering equipment, so might be in use in similar installations.

Description of defect / problem

The unit was switched off to carry out a 5 yearly test and inspection on the equipment bays. This included isolating the UPS which protects the BNCS, desktop and Radioman PCs. The UPS was switched off and the IEC lead which feeds power to it was pulled out.

Once the inspection was complete, power was restored to the UPS and it was switched it back on. The yellow light glowed, indicating power was being supplied via the UPS battery. It appeared to be going through its test cycle. After a while it became clear that it wasn’t going to revert to its incoming mains supply (green light).

It was found that it wasn’t possible to switch off the UPS off and it wasn’t actually powering the equipment it was feeding.

Fairly quickly there was a nasty smell of rotten eggs, traced to the UPS unit which had become very hot. This was caused by the internal battery overheating. It seems likely that there was a component failure in the UPS has caused a short circuit across the battery. It was carefully removed to a place of safety.

After it had cooled down, on closer inspection it was found that the batteries melted and there was other internal damage. See photos below.

Who May Be Affected?

Local radio and other staff in the vicinity, if the problem should occur on other units.

Actions Required1) Ensure you know where each of these is installed.2) Try to ensure that the UPS is maintained at an adequate ambient temperature, as elevated

temperatures can reduce component life and lead to failure.3) Ensure 6 monthly inspections are carried out and recorded.4) When procuring similar equipment, select models which have integral overcurrent and over-

temperature fusing.5) If unit has failed, report on my risks and return to APC www.APC.com.

If you encounter a unit that is overheating the following action is recommended:

1) The first consideration must be staff safety, therefore should an incident like this arise do not compromise your own safety.

2) Isolate the mains supply to the unit and if possible switch it off so it is not producing mains. 3) If it is producing smoke or heat, switch the power off to the area, discharge a CO2 fire extinguisher

over it, leave the area & raise the alarm.4) Be aware that the battery could well be leaking Electrolyte, so therefore should only be handled

after assessing the risk & protective measures have been taken. 5) Consult the APC Data sheet (APC data sheet) before handling.6) Consult www.APC.com for further technical information.

Sources of further information

Company Name: Schneider Electric Incorporated (formerly APC by Schneider Electric, American Power Conversion Corporation)Address: 132 Fairgrounds Road, West Kingston, RI 02892Tel: 800-788-2208 or 401-789-5735Contact: http://nam-en.apc.com/app/askWeb: www.APC.com

BBC Safety Advice Line contacts: BBC Safety Advice Line (Ask AL)Office Hours: 9am - 6pm Mon – FriInternal Tel: 0464External Tel: +44 (0) 370 411 0464E-Mail: ask.al@bbc.co.uk BBC Safety Website:  www.bbc.co.uk/safety

 

Issued by: BBC SafetyBBC Contact: Nick Walker / Richard Perry via the Safety Advice line.Issue Date: 12th February 2014Review / expiry date: 12th July 2014