Single Point of Failure

I recently (inadvertantly) rebooted a DAS in a courthouse by leaning on the wall. Talk about Hall of Shame...

I was troubleshooting the public safety part of an existing multi-carrier DAS, sitting on the floor, hooked up to the DAS head-end.  After a while got tired, and leaned back on the wall. There was a single plug going into the wall outlet which was connected to 2 UPS units, the whole head-end was connected to these 2 UPS units - basically, this DAS had a single point of failure. While I leaned back, I guess, I wiggled the plug and the power connection went out. Although UPS took over, but the latency in the UPS made the DAS reboot (this reboot shoud not have happened, but it did!). 

Besides the fact that I may be few fries short of a happy meal, I learned a few things:

1. Do NOT to use a plug with its stem sticking out. Touching the stem (especially accidentally) may cause problem.

2. Use 90 degree rotating wall plug adapter if you can find one. The "rotating" feature adds obvious flexibility. Check out these example from 3 different manufacturers: Ziotek (shown below), Pro Cord, Panamax (non-rotating).

3. Do not plug the power plug on a wall outlet that may be on the way of walking around. In this particular case, we had an outlet at the corner of the room. This does not eliminate the possibility, but reduces the risk of power outage. If possible make the plugs hard to reach. Plugs itself do not go bad frequently. 

4. Check the health of UPS units periodically if possible. If you are maintaining a DAS, check the health of UPS occassionally. If you have remote monitoring capability into the UPS, then that can be part of the NOC system too.