Cummins/Onan — Testing AC Load Circuit Breaker - Resistance Check
Testing & diagnosis
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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Before you start
- Place Run/Stop/Remote switch in Stop and disconnect battery negative cable.
Procedure
- Disconnect line and load wires from circuit breaker.
- Move breaker handle to On position.
- Check resistance across each pole (line to load).
- Resistance should be very low (near zero) and relatively equal across all poles.
Tools required
- ohmmeter Amazon
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- Resistance near zero
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.