# safety electrical transformer



## frank (Feb 6, 2007)

Installed this isolating tool transformer a couple of weeks ago. 110 volt output with 55 volts to earth ( ground) protected also via 30mA residual device.












Note local fire extingisher in background.


Frank


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## BBQ (Nov 16, 2010)

Frank you may want to explain it a bit more as we have nothing similar in the states. (About the closest we get is for some audio equipment circuits, 125 line to line 60 volts to ground.)

Our job site temps are typically 240 or 208 line to line and 125 volts to neutral and ground with the 125 volt receptacles protected by 6ma ground fault protection.


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## frank (Feb 6, 2007)

BBQ


The transformer is a 10Kva 415 volt 3 wire only with earth. The outputs are 32amp or 16 amp 3 pin to a standard known as IP67 ( water resistant). The output voltages are 110 volt - maximum compulsory voltage here in the UK for temporary construction site supplies. The transformer offers full isolation of secondary from primary for use of non earthed equipment and tools or earth protection for exposed metalic tools and equipment. The second option provides a 110 volt secondary centre tapped to ensure a maximum voltage raised to ground of a maximum of 55 volts. The Primary is also protected via a suitable line circuit breaker and double pole 30mA RCD. The 55 volt fault voltage also equates via math to safe (ish) acceptable volt level tp pass 30 mA through the average body resistance.

Frank


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