Applies To
Intermatic EJ500 (discontinued) and ST01, ST01K, EI600 Series in-wall programmable timers.
Question / Problem
Can I replace my discontinued EJ500 timer with an ST01 timer, and what are the differences between these two timers?
Answer
Yes. The ST01 in-wall programmable timer is a direct replacement for the discontinued EJ500 in most applications. Both timers fit a standard single-gang wall box, do not require a neutral wire connection, and support single-pole and three-way wiring configurations. The ST01 can be installed in the same location as an EJ500 without any rewiring in most cases.
Warning: Replacing an in-wall timer involves working with line-voltage wiring (120-277 VAC). Disconnect power at the circuit breaker before removing the existing timer or installing a new one. If you are not comfortable working with electrical wiring, contact a licensed electrician.
The ST01 provides several improvements over the EJ500, including LED load compatibility, a wider input voltage range, more programmable events, a longer battery backup, and a programmable countdown mode.
Feature Comparison
| Feature | EJ500 | ST01 / EI600 |
|---|---|---|
| Status | Discontinued | Current |
| Load Compatibility | Incandescent only | Incandescent, Fluorescent, CFL, LED |
| Maximum ON/OFF Events | 14 | 40 |
| Battery Type | LR44 (replaceable) | CR2 lithium (replaceable) |
| Battery Backup Time | 100 Hours | 3 Years |
| Astronomic Scheduling | Yes | Yes, uses latitude and longitude for greater accuracy |
| Daylight Saving Time | Yes | Yes |
| Countdown Mode | No | Yes (up to 24 hours) |
| Neutral Required | No | No |
| Wiring Configurations | Single-pole, three-way | Single-pole, three-way |
Tips / Additional Notes
- If you are currently using an EJ500 with incandescent bulbs and plan to switch to LED bulbs, the ST01 supports LED loads while the EJ500 does not. Using LED bulbs with an EJ500 may cause the LEDs to glow dimly when the timer is in the OFF position due to the way the EJ500 passes a small current through the load wire.
- The programming interface on the ST01 is different from the EJ500. You will need to reprogram your schedule after installation. Refer to the ST01 instruction manual for programming steps.