8502 Type S (NEMA Size 1, 27 A)
Square D (Schneider) · NEMA Size 1
The classic Type S NEMA contactor: 27 A continuous, 10 HP @ 460 V. Bulky by IEC standards but built to be rebuilt — contacts, coils and arc chutes all swap in minutes. Thousands still run after 30+ years.
Ratings
- Continuous current
- 27 A
- Hp (3Φ)
- 7.5 HP @ 230 V · 10 HP @ 460/575 V
- Hp (1Φ)
- 2 HP @ 115 V · 3 HP @ 230 V
- Design
- NEMA — withstands 10× rated current on fault clearing
- Single-phase HP
- 2 HP @ 115 V · 3 HP @ 230 V
- Three-phase HP
- 7.5 HP @ 230 V · 10 HP @ 460/575 V
Coil data
- Available coil voltages
- 9998 replacement coil kits: 24, 110/120, 208, 220/240, 277, 440/480, 550/600 VAC
- Inrush VA
- ≈ 245 VA
- Sealed (holding) VA
- ≈ 27 VA
- Pickup voltage
- ≥ 85% of rated (NEMA coils are forgiving on dips)
- Dropout voltage
- 40–65% of rated
Typical measured coil resistance (±15%, ballpark)
120 VAC (9998-SO4 family)≈ 45–80 Ω
240 VAC≈ 180–320 Ω
480 VAC≈ 700–1,200 Ω
OL = open coil · near zero = shorted turns · coil-to-frame must read >1 MΩ.
Coil resistance checker
Pick the coil voltage, enter your meter reading across A1–A2 (coil disconnected), and compare it to the expected ballpark.
Ω
This model (120 VAC (9998-SO4 family) table value)45 Ω–80 Ω
Generic small-frame 110–120 VAC150 Ω–450 Ω
Readings 2× high usually mean heat damage and a coil near end of life. Ballpark only (±15%+); electronic wide-range coils (e.g. ABB AF) read misleading values — test those at rated voltage instead. Always measure coil-to-frame too: must be >1 MΩ.
Terminals & accessories
Power/coil terminals: L1/L2/L3 top, T1/T2/T3 bottom; coil A1/A2 on the front
Auxiliary contacts: 9999 SO-11 etc. aux contact kits; field-addable NO/NC
Companion overload: Melt-alloy or bimetal thermal units (Class 8536 starter adds the overload block)
Cross-references
Field notes
- Humming but not pulling in? The shading coil (copper ring on the pole face) is cracked — buzz → heat → dead coil.
- Rebuild kits (9998 contacts + coil) cost a fraction of a new contactor and install with a screwdriver.
- NEMA sizing is deliberately conservative — a Size 1 is roughly an IEC 30 A device with far more fault headroom.