Forum Posts

• January 19, 2020 2:38 AM PST

  in the topic Transformer impedance in the forum Electrical Engineering

  Due to full load there is always voltage drop to the winding resistance and leakage reactance. This is called Z%. This impedance represents the amount of normal primary voltage that should be applied to the transformer to produce full rated load current when the secondary winding is short circuited. The maximum short circuit current that can be obtained from the output of the transformer is limited by the impedance of the transformer and is determined by multiplying the reciprocal of the impedance times the full load current. This post was edited by Ronnie Rana at January 19, 2020 2:38 AM PST
• December 26, 2019 8:45 AM PST

  in the topic NEC 277v motors in the forum Electrical Engineering

   Motors rated at 277 volts are not as common as other voltages but are sometimes used within equipment that has an overall nameplate. The equipment nameplate value can be used in that situation as stated in 430.6(A)(1) Exception No. 2. If being installed as a separate motor make sure all of the other applicable rules of Article 430 are complied with, including 430.7. If there is no table value given in the NEC then the only choice is to use the nameplate value or get the value from the motor manufacturer.
• December 12, 2019 1:36 PM PST

  in the topic Electricity theft in the forum Electrical Engineering

  Hello everybody.I have been living in the same house for 7 years now.In the first six years I used a total of 15,000 kWh. That is an average of 2,500 kwh per year. Everything was always fine and good.In March 2018, a new   meter was installed due to renovation work.Since February 2019 I have been using around 8,000 kWh a year according to the electricity provider.I have now noted the shower time every day, what goes on for how long, etc.but the power consumption does not seem some how correctlyYesterday I was not taking a shower for the test, no washing machine. Only an oven ran for an hour. But no light, no PlayStation or anything else. I used 15 kWh again.Yesterday evening 8 p.m. until 8 am this morning again 8 kWh although we only slept and nothing was running.How can I prove something is wrong?I got all the fuses out at 9 a.m. and I'm curious to see if the meter continues to run
• December 7, 2019 10:22 AM PST

  in the topic ground fault protection in the forum Electrical Engineering

  Ground fault protection of equipment is not allowed per NEC 695.6(G)
• November 17, 2019 12:05 PM PST

  in the topic 60A fuse in the forum Electrical Engineering

  (27A × 1.25) + 14A = 48A 8 AWG rated 50A at 75°C largest branch circuit ground fault and short circuit protective device : 20 hp motor = 27A × 2.50 = 68, next size up = 70A the feeder protection: not more than 70A + 14A, = 84A. Next size down = 80A Therefore, for this specific arrangement, you would use 8 AWG conductor and an 80A breaker.