Cutler-Hammer Generator Interlock Kit & Inlet Wiring Guide
Connecting a 240V portable generator inlet (NEMA 14-50, L14-30, 14-30, or 6-50) to a Cutler-Hammer load center requires a mechanical interlock plate matched to the main breaker layout (CHMIKCSR), a listed CH 2-pole backfeed breaker, and a mechanical breaker hold-down retainer per NEC 408.36(D).
By Gil Sapir, Editor
Fast Answer⚡ Interlock Reference: Cutler-Hammer Load Centers▼
Mechanical Interlock Kit (CHMIKCSR) + CH Backfeed Breaker
30A or 50A Double-Pole CH Breaker • 6 AWG THHN Cu (50A Inlet) or 10 AWG Cu (30A Inlet)
Compatible Generator Inlet Configurations for Cutler-Hammer
Comparison of NEMA 14-50, 14-30, 6-50, and L14-30 generator inlets when wired to a Cutler-Hammer load center.
| Generator Inlet | Max Breaker / Amps | Continuous Load (80%) | Max Running Watts | Copper Wire Gauge | Pin Configuration |
|---|---|---|---|---|---|
| NEMA 14-50 (240V) | 50A 2-Pole (CH) | 40A | 12,000 W peak | 6 AWG Cu (THHN) | 4-wire RV/Generator Inlet |
| NEMA 14-30 (240V) | 30A 2-Pole (CH) | 24A | 7,200 W peak | 10 AWG Cu (THHN) | 4-wire Dryer/Generator Inlet |
| NEMA 6-50 (240V) | 50A 2-Pole (CH) | 40A | 12,000 W peak | 6 AWG Cu (THHN) | 3-wire Welder/Generator Inlet |
| NEMA L14-30 (240V) | 30A 2-Pole (CH) | 24A | 7,200 W peak | 10 AWG Cu (THHN) | 4-wire Twist-Lock Generator Inlet |
Cutler-Hammer Load Center Configurations & Interlock Reference Matrix
All 10 Cutler-Hammer panel variants, main bus ratings, branch breaker types, and interlock kit references.
| Panel Configuration | Main Rating | Branch Breaker Type | Interlock Reference Model |
|---|---|---|---|
| Cutler-Hammer CH Series 200A Main Breaker | 200A | Type CH | CHMIKCSR |
| Cutler-Hammer Tan Handles 100A Vintage | 100A | Type CH | CHMIKCSR |
| Cutler-Hammer CH Series 125A Main Breaker | 125A | Type CH | CHMIKCSR |
| Cutler-Hammer CH Vintage 150A Panel | 150A | Type CH | CHMIKCSR |
| Cutler-Hammer CH Main Lug 200A Panel | 200A | Type CH | CHMIKCSR |
| Cutler-Hammer CH 225A Commercial | 225A | Type CH | CHMIKCSR |
| Cutler-Hammer BR Series 125A | 125A | Type BR | BRMIKCSR |
| Cutler-Hammer Outdoor NEMA 3R 100A | 100A | Type CH | CHMIKCSR |
| Cutler-Hammer Outdoor NEMA 3R 200A | 200A | Type CH | CHMIKCSR |
| Cutler-Hammer CH 40-Space 200A Main | 200A | Type CH | CHMIKCSR |
Generator NEMA 14-50 Inlet → Cutler-Hammer CH Series 200A Main Breaker Panel Wiring
Required Hardware Checklist for Cutler-Hammer
🔧 Mechanical Interlock Kit (CHMIKCSR)
Matched to Cutler-Hammer main-to-branch breaker spacing. Physically prevents turning on the generator backfeed breaker while the main utility breaker is closed.
Check Retailer Availability on Amazon🔌 Outdoor Generator Power Inlet Box (30A / 50A)
NEMA 3R weatherproof generator inlet box (NEMA 14-50 / CS6365 for 50A or NEMA L14-30 for 30A) wired to a listed 2-pole CH backfeed breaker with hold-down kit.
Check Inlet Box Availability on AmazonRequired Wiring & Installation Accessories
50A Double-Pole Circuit Breaker
UL-Listed, mandatory for continuous EV charging load under NEC code.
6 AWG THHN Copper Wire (50ft Spool)
Heat-resistant 90°C copper conductor for conduit installation.
Hubbell HBL9450A / Bryant Electric 50A Industrial NEMA 14-50 Outlet
Industrial Grade heavy-duty receptacle (Hubbell HBL9450A / Bryant 50A). Mandatory safety upgrade to prevent melting on high continuous EV loads.
3/4" Schedule 40 PVC Conduit (10ft Lengths)
UV-resistant protection for exposed indoor/outdoor wire runs.
Generator Interlock Guides for Other Panel Lines
View NEC Article 702 interlock compatibility across other residential load center series:
Interlock Compatibility FAQ: Cutler-Hammer
Is a mechanical generator interlock kit compliant with NEC code for Cutler-Hammer panels?
Yes. Per NEC Article 702.5, a listed mechanical interlock plate physically prevents both the main utility breaker and the generator backfeed breaker from being turned on simultaneously in a Cutler-Hammer load center, and NEC 408.36(D) requires a mechanical hold-down retainer on the backfed plug-on breaker.
What size wire and breaker are required for a 50A or 30A generator inlet on a Cutler-Hammer panel?
A 50A generator inlet (NEMA 14-50 or CS6365) requires a 50A double-pole CH-type breaker with 6 AWG THHN copper wire in conduit (or 6/3 NM-B where permitted). A 30A generator inlet (NEMA L14-30 or 14-30) requires a 30A double-pole CH-type breaker with 10 AWG copper wire.
Which Cutler-Hammer panel ratings are covered on this page?
This guide covers all 10 residential Cutler-Hammer configurations, including CH Series 200A Main Breaker, Tan Handles 100A Vintage, CH Series 125A Main Breaker, CH Vintage 150A Panel, CH Main Lug 200A Panel, CH 225A Commercial, BR Series 125A, Outdoor NEMA 3R 100A, Outdoor NEMA 3R 200A, CH 40-Space 200A Main, using CH branch breakers and reference interlock kit CHMIKCSR.