I live in a home that is 50 plus years old. All of the electrical outlets in the home are the out dated 2 prong plug ins. Are there any safety issues associate with replacing the outdated 2 prong outlet with a 3 prong outlet to power a metal halide high bay light fixture with a 400 watt ballast? The wiring in the wall is also outdated and does NOT have the up to date 3 wire electrical supply.
You can run it but its not advisable without the extra ground. You also want to see what the breaker rating is for the circuit and check the existing load on it. It will add about 3.5 amps to the load so stay under the breaker size by 15% for having bad wire. If breaker is 15 amps and is already loaded to 9 amps your lamp adds 3.5 amps for a total of 12.5 amps its ok because 12.75 is as high as you should go because we derated for bad wire.
no, use a ground wire for safety.
No, because the fixture has a transformer, and if the transformer fails it can energize the metal parts of the fixture. The purpose of a ground is to provide a current path to ground from the chassis to operate the overcurrent device if the chassis becomes energized. Without a ground wire the current may find another current that may ignite combustibles.
The ground is for safety in case of a condition where the case of the fixture may be energized. If the fixture is beyond reach from the ground, the lack of the ground wire is a non issue. Unplug the fixture and let it cool before touching it. As to the lack of a ground in the connection box, mark that receptacle with a permanent label that it has no ground. Harvest the plants when fully mature.
No the electrical code requires a ground. Run a separate ground wire to it from the metal water line coming into the home or from the ground rod from the electrical service or Telephone ground rod.
