Series 12X
Shortstop Circuit Breakers
Specifications
Single Pole Thermal Type Breakers
Applications: Battery chargers, trucks, buses, RVs,
trolling motors, etc
Rating: 5-50A, 14VDC; 28VDC (Series 123, 124, & 125)
Interrupt Rating: Main Circuit Protection: 1.5kA @ 12VDC (Series 123
w/plastic cover); Branch Circuit Protection: 2.5kA @ 12VDC (Series
121 & 124 -01 sealed & Series 123 w/plastic cover)
Operating Temperature Rating: 40F (40C) to 185F (85C)
Storage Temperature Rating: 40F (40C) to 260F (125C)
Materials: Black UL-Rated thermoplastic body (thermoset for Type
II body & buttons). Cover is grey thermoplastic or steel-Type l gold,
Type ll silver
Marking: Custom marking available. Consult factory for options
Termination: #10-32 thread and quick-connect options available
Torque Rating: 24 in-lbs (2.7N m) max
Mounting Torque Rating: Plastic cover - 15 in-lbs (1.7N m);
Metal cover - 30 in-lbs (3.4N m)
Ingress Protection Rating: IP66 On plastic cover version only (except
for terminals)
Compliances: SAE J553; SAE J1171 (ignition protected)
EATON Commercial vehicle solutions 99Ordering information
12X X XX - X X X - XX - XX
Series Terminal Rating Bracket Mtg. Holes Cover* Options Hardware
121 = Type I, 12 VDC A = Two 10-32 studs; .66 (Aux), .56 (Bat) 05 = 5 amps 0 = No bracket 0 = No bracket M = Metal 01 = Waterproof (metal WA = Whiz-lock nut
122 = Type II, 12 VDC B = Two 10-32 studs; .56 (Aux & Bat) 08 = 8 amps A = Bracket 1 = .140 dia. P = Plastic covers only) assembled
123 = Type III, 24 VDC C = Two 10-32 studs; .66 (Aux & Bat) 10 = 10 amps B = Bracket 2 = .196 dia. WB = Whiz-lock nut bulk
124 = Type I, 24 VDC D = Two .250 QC; (Aux & Bat)*** 12 = 12 amps C = Bracket 3 = .237 dia. (metal only) 02 = Splash proof HA = Nut & lock washer
125 = Type II, 24 VDC H = One 10-32 stud .56 (Bat), 15 = 15 amps E = Bracket 4 = .265 dia. (plastic only) (optional on metal assembled
Double .250 QC Aux)** 20 = 20 amps (plastic only) 5 = .228 dia. (plastic only) covers - add 02 sufx; HB = Nut & lock washer bulk
L = Two 10-32 studs; .37 (Aux & Bat) 25 = 25 amps 6 = .221 dia. (metal only) std. on plastic covers - KA = Keps lock nut assembled
30 = 30 amps omit 02 sufx.) KB = Keps lock nut bulk
35 = 35 amps
40 = 40 amps
50 = 50 amps
*Series 123 available in plastic cover only.
Series 122 & 125 available in metal cover only.
**40A maximum
***30A maximum
Please consult factory regarding conguration availability.
Temperature Derating / Time Current Curves
Temperature Derating Curves
200
150
10 amps & below
typical curve
15 amps & above
100
typical curve
50
0
0 50 100 150 200 250 300
Ambient Temp.
o
(in C)
Trip Time vs. % Rated Current
1000
100
10 amps & below
typical curve
10
15 amps & above
typical curve
1
0.1
100 200 300 400 500 600
% of Rated Current
EATON Commercial vehicle solutions 101
Maximum % Hold Current