This time we are at the early stage of a new site going live. Builders everywhere, floor tiles up all over, cabling going in and the electrician has just compl                                                                      eted the two new 4kw supplies for my main access switch. Great, we can get on with bringing this switch online and get it commissioned.

So I power up the switch one supply at a time and watch it boot whilst wondering, as I always do, “why do the fans need to be operating at full blast during the power up?”

Then weirdness starts. One of the switch’s power units shuts down. Never seen that before. Then it’s back. A short period later, off it goes again. This is definitely going to make for an interesting commissioning and testing session.

First call is to the electrician to come and watch this. He obliges and watches in amusement but it’s clear to him it’s not his fault, there is electricity, it is our kit that is at fault.

Hmm. Not sure I believe that but let’s see if I have anything of use, these switches have all manner of diagnostics on them so let’s see what power based questions I can ask.

After some poking around I can trigger interesting console messages that start to tell me that the switch itself is shutting of the power supply to protect itself. I had no idea it could even do that, they certainly don’t mention any of this in training! The next step is of course, why shut down, what is it seeing? Power surge seems to be the answer and the switch does not like that. What a clever thing!

I am contemplating the next move and I hear a slight crackle. Then the switch cuts the power again. Hmm. Crackles suggest arcing, which suggests bad contacts somewhere or a path to earth somewhere there should not be. There is only one real connection point here, that being the commando socket so it’s time to investigate that.

Having turned off the power to the affected supply, I disconnect the commando socket and low and behold the pins on my plug have developed “nipples”. A sure sign of arcing, suggesting bad contact between the plug and socket. Where is that sparky?

Of course once I show the evidence, yes he figures out the socket he has provided is not quite correct and a new one is needed. Phew, crisis averted. Onwards!