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The SOUTHWIRE 40150N is a dual-range, non-contact AC voltage detector built for electrical diagnostics in residential, commercial, and industrial settings. It detects live voltage without requiring direct contact with a conductor, reducing exposure risk during live-circuit testing. The unit covers two detection ranges: 100 to 1,000 VAC for standard line-voltage work and 12 to 1,000 VAC for low-voltage applications. At 6.5 inches in length and 1 inch in width, it fits easily in a tool pouch or chest pocket. Power comes from two AAA 1.5V batteries. Licensed electricians, HVAC technicians, and maintenance professionals rely on non-contact voltage testers as a first-check safety tool before touching any conductor or terminal.
This detector suits a wide range of electrical work, including panel inspection, outlet and switch testing, junction box verification, and low-voltage circuit checks. The 12 to 1,000 VAC lower range makes it useful for doorbell transformers, thermostat wiring, and other low-voltage control circuits in addition to standard 120V and 240V branch circuits. The advanced dual-range capability means a single tool covers both control-voltage and line-voltage environments without swapping instruments.
Designed for general-purpose AC voltage detection across residential, light commercial, and industrial electrical systems operating within the 12 to 1,000 VAC range.
Non-contact voltage testers are used by licensed electricians and qualified technicians as a preliminary safety check before servicing electrical circuits. Always de-energize and lock out or tag out circuits per OSHA and NEC guidelines before performing hands-on work, even after a no-voltage indication. Verify the tester is functioning correctly by testing it on a known live source before and after each use. Battery replacement should be performed with the unit away from any energized equipment.
We pulled together the parts most installs need for this unit, plus a few add-ons worth a look. Check what you need — nothing here blocks checkout.
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