Step 1:

Identify Switchboard/Panelboard Type:

Circuit Breaker Type:

Model: Year:

Brand: Twin or Single: Twin Single

Step 3:

Measurements for "A":
(Distance from center to center on bus bar)
Measurements for "B":
(Distance from rail to rail)
Measurements for "C":
(Inside Support Rail to Face of C/B)
Measurements for "D":
(Distance from face of bus bar to top of C/B)