How to Connect a Portable Generator to a House
A portable generator should power a house only through approved transfer equipment or direct extension-cord loads—never by backfeeding a receptacle.
Connecting a generator to a household panel changes the electrical system and should be planned and installed by a qualified professional.
The goal is to isolate the home from utility power, protect workers and keep the generator within its voltage and load limits.
Use a Transfer Switch or Approved Interlock
Install an outdoor inlet, correctly sized cord and listed transfer switch or approved panel interlock. Never use a male-to-male cord or feed a dryer outlet.
Connection Verdict
Direct extension cords are simplest for a few appliances. Transfer equipment is the correct solution for furnaces, pumps and household circuits.
Safe Connection Options
| Method | Best For | Installation |
|---|---|---|
| Heavy-duty extension cords | A few plug-in appliances | No panel work |
| Manual transfer switch | Selected household circuits | Professional installation |
| Panel interlock | Flexible panel circuit selection | Professional installation and compatible panel |
| Automatic transfer | Specialized portable/standby systems | Professional design |
Manual Transfer Switch
A manual transfer switch mechanically or electrically prevents utility and generator sources from energizing the panel at the same time. It commonly powers a fixed group of essential circuits.
Generator Interlock
A listed interlock mechanically prevents the main breaker and generator breaker from being on together. It must match the exact panel and meet local requirements.
Outdoor Inlet and Generator Cord
The inlet provides a weather-resistant connection point. Cord ampacity, plug type, voltage and breaker size must match the generator and installed equipment.
Typical Safe Operating Sequence
Place Generator Safely
Outdoors at least 20 feet away.
Inspect Equipment
Check cord, inlet and generator.
Turn Off Transfer Loads
Reduce startup demand.
Connect the Cord
With generator off unless manual says otherwise.
Start and Stabilize
Warm up as directed.
Transfer Source
Use the installed switch or interlock.
Add Loads Gradually
Watch running and surge limits.
Reverse the Sequence
Unload, transfer back, cool and shut down.
What You Must Never Do
Never Backfeed a Receptacle
It can energize utility lines.
Never Use a Male-to-Male Cord
It exposes live prongs.
Never Bypass the Main Breaker
Transfer equipment must create isolation.
Never Exceed Cord Rating
Heat and fire can result.
Never Ignore Neutral/Ground Design
Bonding must match the transfer system.
Never DIY Beyond Competence
Panel work requires qualified installation.
Frequently Asked Questions
Can I plug a generator into a dryer outlet?
No.
Is an interlock as safe as a transfer switch?
A listed, correctly installed interlock can be safe where permitted.
Do I need an inlet box?
It is the standard connection point for many transfer setups.
Can I install it myself?
Electrical panel and transfer work should be done by a qualified professional.
Can a 120V generator power both panel legs?
Only through specifically designed equipment and with major limitations; never improvise.
Do I need a grounding rod?
Grounding and bonding depend on the generator and transfer configuration.