WiremanWireman · Portable generator and inlet: no power: troubleshooting for electricians · 2023 NEC ·
Portable generator and inlet: no power
Generator, cord, inlet and interlock, one link at a time. Never a dryer outlet.
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How it works
A portable generator connects to a house through a listed power inlet, a cord, and transfer equipment: either a manual transfer switch or a listed interlock on the panel that makes it impossible for the main and the generator breaker to be on at the same time. That transfer equipment is what keeps generator power from backfeeding the utility lines, where it can kill a line worker. Connecting a generator through a dryer or range receptacle with a double-male cord, without that equipment, is never safe.
Every question and answer in this guide. Tap “Step by step” to walk through it.
- How is the generator connected to the house?
- Inlet with an interlock or transfer switchTest: Check voltage at the generator receptacleExpect: About 240 V across the hots and about 120 V from each hot to neutral.
- No voltageThe generator isn’t producing
- Only one hot has voltageOnly one leg is getting through
- Both legs normalTest: Test the cord end to endExpect: Each conductor continuous end to end, and no continuity between conductors.
- A conductor is open or shortedDamaged generator cord
- Cord tests goodTest: Measure at the generator breaker in the panelExpect: About 240 V across the poles and 120 V to neutral, and power at the circuits once the generator breaker is on.
- No voltage at the breakerInlet or the wiring to the panel
- Voltage present, circuits still deadBreakers or interlock position
- 120 V circuits work only on one sideOnly one leg is getting through
- Cord into a dryer or other receptacleBackfeeding without transfer equipment
- Inlet with an interlock or transfer switchTest: Check voltage at the generator receptacleExpect: About 240 V across the hots and about 120 V from each hot to neutral.