TKlosterman
Member
- Location
- Northwest/West Coast Out of WA
Hey guys, been a while since I have been on. I would like to try and pick the smartest brains I know. We are a NETA certified company and have been in business for quite a few years. I have recently ran into a horrifying situation. We are doing acceptance testing on new switchboards at a new construction site. We do all of our component testing first then the system in its entirety. While testing CT/PT circuits we found the following;
1. CT Shorting blocks, in the same lineup we found the CT wiring coming in from left side then right side, from top and then bottom. I cannot find a standard requirement for this besides poor workmanship. If you are in the maintenance side or testing side you can understand the hazards involved with this. If you short the CT block and remove the meter wires under load, no issue. go to the next section and remove from the same side, but this time you just removed the CT wire while under load, it will arc, spark and probably burn up the CT.
2. They have also routed the CT wires through DIN rail plastic blocks. From everything I could find on these is they are only rated for 20 amps. Now I understand under normal operating conditions we are usually under five. But under fault conditions the CT will push in excess of 100A on it's secondary. Does not seem like a safe practice.
3. The last thing, just to keep this from turning into a punch list, they wired the CT's in 12AWG SIS wire. Finally something right! But just before it hit the meter, they went to DIN rail again and dropped wire size down to 14AWG.
What I am looking for is hard proof "ANSI,NEMA,IEEE" standard on safety and hazards involved with this kind of poor craftsmanship. Any help at all would be greatly appreciated.
1. CT Shorting blocks, in the same lineup we found the CT wiring coming in from left side then right side, from top and then bottom. I cannot find a standard requirement for this besides poor workmanship. If you are in the maintenance side or testing side you can understand the hazards involved with this. If you short the CT block and remove the meter wires under load, no issue. go to the next section and remove from the same side, but this time you just removed the CT wire while under load, it will arc, spark and probably burn up the CT.
2. They have also routed the CT wires through DIN rail plastic blocks. From everything I could find on these is they are only rated for 20 amps. Now I understand under normal operating conditions we are usually under five. But under fault conditions the CT will push in excess of 100A on it's secondary. Does not seem like a safe practice.
3. The last thing, just to keep this from turning into a punch list, they wired the CT's in 12AWG SIS wire. Finally something right! But just before it hit the meter, they went to DIN rail again and dropped wire size down to 14AWG.
What I am looking for is hard proof "ANSI,NEMA,IEEE" standard on safety and hazards involved with this kind of poor craftsmanship. Any help at all would be greatly appreciated.