Consider a situation where a barn, cabin, or outbuilding is set far away from where the main electrical service terminates. A long cable run at 120/240 must be made to the outbuilding. To minimize voltage drop, and the subsequent undesirable effects of low system voltage, electricians often rely on some common strategies:
- Increasing cable size
- Reducing cable length
- Paralleling conductors
Using a pair of distribution transformers is a 4th option. Stepping up the voltage to 300/600 for the long cable run, and then down to 120/240 in the outbuilding can provide a technically and economically superior solution to simply oversizing cables.
- By making the long run at 300/600, you can reduce the amperage in the cable and select a smaller wire gauge to save money in cabling.
- By having a 600 to 120/240 transformer in the outbuilding, it allows an electrician to change the transformer taps to fine-tune the output voltage and mitigate even the smaller voltage losses across the 600v cable run.
|Conceptual one-line of a basic installation of two transformers in a step-up-step-down arrangement.|
|Wiring and connection details of a 240 to 300/600 transformer and a 600 to 120/240 transformer.|