NEMA L14-30 Generator Inlet to Square D QOB Commercial 225A Panel Interlock Kit & Wiring
Safely connecting a 240V / 30A (L14-30) generator outlet to your Square D QOB Commercial 225A Panel panel requires matching the physical interlock plate to the top-right or top-left breaker slots where your main breaker is located.
Generator NEMA L14-30 Inlet → Square D QOB Commercial 225A Panel Panel Wiring
Required Hardware Checklist for Square D QOB Commercial 225A Panel
🔧 Mechanical Interlock Kit
Must match Square D QOB Commercial 225A Panel Series. Designed for QOB-type breakers. Prevents turning on generator power while main utility power is connected.
Find Matching Interlock Kit on Amazon🔌 Outdoor Generator Inlet Box
NEMA L14-30 male inlet box rated for 30A / 240V. Configuration: 4-wire Twist-Lock Generator Inlet.
Find NEMA L14-30 Inlet Box on AmazonRequired Wiring & Installation Accessories
30A Double-Pole Circuit Breaker
UL-Listed, mandatory for continuous EV charging load under NEC code.
10 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.
Interlock Compatibility FAQ
Is a mechanical interlock kit compliant with NEC code?
Yes. Per NEC 702.12, an interlock plate physically prevents both the main breaker and the generator backfeed breaker from being turned on simultaneously, fulfilling code safety requirements.
What wire size is needed for a NEMA L14-30 inlet?
A NEMA L14-30 (30A) inlet requires 10 AWG THHN copper wire.