Three Phase voltage meters

[wireday]

We have a manufacturing plant that I do work for.They would like to monitor there 480 volts coming into the facility.
A engineer at the plant wants to simply purchase some random meters and run a number 12 guage wire to them.I have never installed any of these but have had a chance to look some over.They were nice kits that had features like a nice display and an off position.Is there any code issues with this? Is one way correct over the other? Thanks

 

[GoldDigger]

The code does not care about how you make the measurements as long as any wires involved are appropriately protected against short and overcurrent.

 

[wireday]

I agree, the set ups that Ive seen used CT's and would switch phase to phase and line to neutral as well.

 

[Jraef]

I agree, the set ups that Ive seen used CT's and would switch phase to phase and line to neutral as well.

A CT is used for measuring CURRENT, not voltage. Did you mean a PT- Potential Transformer?
that is often used when there is a need to avoid running the line voltage to the meter, often for safety reasons. So for example if you have a 480V system but you are uncomfortable running 480V wires to a meter on the door, then you use 4:1 PTs tht step the 480 down to 120V, then set up your meter to read 480V when it receives 120V. also, some meters are DESIGNED to only accept a lower voltage like that, so PTs are necessary whenever the line voltage is above 120V. RTFM.

If there are CTs, and this is a Ammeter (or Pwer meter), not a volt meter, then there are additional issues with regard to safely connecting the CT circuits through what are called "Shorting Blocks". When you have CTs in a circuit, allowing them to go "open circuit" meaning the CT output is not connected to anything, creates a very dangerously high voltage on the CT wires. So if you must replace or measure current without first shutting down all power, you need to be able to short out the CT wires during that process. The "shorting blocks" are specializes terminal blocks that facilitate this.

 

[meternerd]

We have a manufacturing plant that I do work for.They would like to monitor there 480 volts coming into the facility.
A engineer at the plant wants to simply purchase some random meters and run a number 12 guage wire to them.I have never installed any of these but have had a chance to look some over.They were nice kits that had features like a nice display and an off position.Is there any code issues with this? Is one way correct over the other? Thanks

Monitoring? Are you having voltage problems? If you're interested in possible high or low voltages, you might look into a peak type meter that stores min and max voltages and is resettable. Much cheaper than a power quality monitor and would probably give you some useful information. Many do not require transformers. Some even have data ports so you can monitor them with a computer. Just protect the inputs with 600V fuses and fuse blocks for safety.