Cummins/Onan — Checking Shunt-Trip Operation
Testing & diagnosis · Circuit breaker shunt trip
From a Cummins/Onan service manual covering: 4BT3.9-GC1, 4BT3.9-GC2, 6BT5.9-GC1, 6BT5.9-GC2, 6CT8.3-GS/GC1, 6CTA8.3-GS/GC1, 6CTA8.3-GS/GC2. Check it applies to your exact model before use.
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Procedure
- Refer to original equipment order and wiring diagrams to confirm signal source connections.
- Apply appropriate signal voltage (12-VDC; 240-, 480-VAC).
- Shunt-trip solenoid should energize and trip breaker open.
- If breaker did not trip, remove signal source.
- Perform continuity check of interconnect wiring and shunt-trip solenoid lead wires.
- Replace interconnect wiring if defective.
Tools required
- multimeter Amazon
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- 12-VDC Amazon Amazon eBay eBay $69.95 FridayParts $11.85 SinoCMP $65.00; 240-, 480-VAC signal
Source: Cummins/Onan service manual. Steps and values are as documented; always cross-check against the official manual and any later revisions for your exact serial number before servicing.