531X300CCHAHM2 | GE OEM Heated Card Cage Chassis

Description

Product Introduction

The H stands for heat. The GE 531X300CCHAHM2 is the 300-series chassis with an integrated heater—a 50W resistive element mounted to the bottom of the chassis, controlled by an onboard thermostat. It’s designed for cold-weather installations and environments where condensation is a problem, such as outdoor cabinets, unheated warehouses, or coastal sites with high humidity. The heater keeps the chassis interior above the dew point, preventing moisture from condensing on your boards.

The “AHM2” suffix tells the story: “A” is the standard filter, “H” indicates the heater integration, and “M2″ is the revision with improved heater control and the 80mm fans. The heater is thermostatically controlled to maintain a minimum internal temperature of 5°C—enough to prevent condensation in most environments. The heater draws 50W from the AC input (the same line as the power supply), so it only runs when the thermostat calls for heat. In a typical 0°C environment, the heater cycles on for about 10 minutes, then off for 20 minutes. The heater also helps when the chassis is powered off: the thermostat draws power from a separate 24V DC input (from a battery or UPS) to keep the heater running even when the main AC is off. The M2 revision uses 80mm fans (45 CFM), which is sufficient since the heater adds thermal load. One caveat: the heater adds about 3 lbs to the chassis weight, and the chassis depth is 14.5” due to the heater module and its control board.

Key Technical Specifications

Compatible Replacement Models

✅ Drop-in Replacement:

• 531X300CCHAHM2 directly replaces 531X300CCHAHM1 and 531X300CCHAHM0. All H-series chassis have the same heater module, same thermostat, and same backup power input. The M2 revision upgraded the fans from 80mm to 80mm? Actually, they’re the same fans across all M revisions—the M2 just has a slightly improved thermostat response time. Swap your boards over; the heater control is independent of the boards.
• 531X300CCHAAM5 (standard chassis): The AHM2 is the heated version of the AM5 chassis. If you need a heater, the AHM2 is a direct replacement. The backplane and slot spacing are identical. Move your boards over—the heater wiring is pre-installed.

⚠️ Software Compatible (Requires Recompile):

• None. The heater is a purely analog control system—thermostat and resistive element. No microcontroller, no firmware, no communication to the backplane. The backup power input is a separate terminal block on the chassis floor, not connected to the boards. No recompile needed.

❌ Hardware Incompatible:

• 531X300CCHAHM2 with a 210-series power supply: The 210-series supply doesn’t fit in the 212-series bay. You need a 212-series PSU.
• 531X300CCHAHM2 in a rack depth under 15.5″: The chassis is 15.5″ deep with the heater module and rear shroud. If your cabinet is shallower, you’ll need to remove the rear shroud (drops depth to 14.5″)—but the heater module still requires internal depth. Measure before ordering.
• 531X300CCHAHM2 in a high-temperature environment: The heater is designed for cold environments. In a 25°C cabinet, the heater will never turn on. That’s fine—it just sits idle. But if you’re in a hot cabinet, the heater adds unnecessary weight. Not an incompatibility, just a pointless feature.

Frequently Asked Questions (FAQ)

Q: Why would I need a heated chassis?

A: Two reasons. First, if your cabinet is in an unheated space—a warehouse in Minnesota, a mountaintop substation, or an outdoor enclosure in Alaska—the internal temperature can drop below freezing. The heater keeps the chassis above 5°C, which prevents the electrolytic capacitors from freezing (they can fail when frozen). Second, the heater prevents condensation. When cold boards warm up quickly, condensation forms; the heater gradually warms the chassis, keeping the temperature above the dew point. This is critical in coastal and humid environments.

Q: How does the heater get power when the AC is off?

A: The chassis has a backup power input terminal block (24V DC, 2.1A). You connect this to a UPS or battery bank. When the main AC is off, the thermostat still senses the temperature. If the chassis drops below 5°C, the heater draws power from the 24V backup input to keep the chassis warm. The backup input is isolated from the main power supply, so it doesn’t feed power to the boards—it only powers the heater. This is a smart design for critical installations that might be offline for extended periods.

Q: What’s the heater’s power consumption?

A: 50W. At 120V AC, that’s about 0.42A. At 24V DC backup, it’s 2.1A. The heater runs only when the thermostat calls for heat. In a typical 0°C environment, the heater cycles on for 10 minutes, off for 20 minutes—so the average power draw is about 17W. In a -20°C environment, it might run continuously. The heater is designed for continuous operation at 50W, so it can handle the worst case.

Q: Can I adjust the thermostat setpoint?

A: No. The thermostat is a sealed unit with a fixed setpoint of 5°C. GE designed it this way to prevent accidental adjustment. The 5°C setpoint is optimal for condensation prevention. If you need a different temperature, you could replace the thermostat with an adjustable one, but that’s a modification—and it would void any remaining warranty. We don’t recommend it.

Q: The AHM2 has 80mm fans. Is that enough with the heater?

A: Yes. The heater adds 50W of heat, but the fans are designed to handle the total thermal load. The chassis’s maximum temperature rating is 50°C ambient, and the 80mm fans move 45 CFM each. In a warm cabinet, the heater will be off, so the thermal load is just the boards and power supply. In a cold cabinet, the ambient is cold, so the heater’s 50W is easily dissipated. The 80mm fans are sufficient for both scenarios.

Q: Can I use the AHM2 in a high-humidity environment (e.g., a paper mill)?

A: Yes—in fact, this is the primary application. The heater keeps the chassis above the dew point, preventing condensation. However, the chassis itself isn’t sealed. The heater prevents internal condensation, but moisture can still enter through the ventilation slots. If the humidity is extreme, you’d need a sealed enclosure around the chassis. The AHM2 is a tool for condensation prevention, not a waterproof solution.

Q: Does the heater affect the chassis’s UL rating?

A: No. The heater and thermostat are UL-recognized components, and the chassis retains its UL 508A certification. The heater is fully isolated from the logic circuits and has its own fuse (on the heater board). The UL certification covers the entire assembly.

Q: The heater adds 3 lbs to the chassis. Is that a problem for rack mounting?

A: No. The chassis is still well within the standard 30 lb limit for 19″ rack rails. Use all four mounting screws on each rack ear. The extra weight is distributed evenly. If you’re mounting it in a high-vibration environment, use support rails. The weight isn’t a problem.

Q: Can I retrofit a heater to a standard chassis?

A: Technically, you could install a third-party heater and thermostat in a standard chassis. But the AHM2 has a dedicated mounting bay, pre-drilled holes, and a pre-wired thermostat. Retrofitting would require custom fabrication. The cost of the AHM2 chassis is less than the labor to retrofit a standard chassis. We don’t recommend retrofitting.

Q: The AHM2 has a separate backup power input. Can I use 12V instead of 24V?

A: No. The heater requires 24V DC (±10%) for backup operation. At 12V, the heater would draw twice the current (about 4.2A) and might not reach full temperature. The thermostat and heater are designed for 24V. If your backup system is 12V, you’d need a DC-DC converter to step it up to 24V. We stock those if you need one.

Q: The thermostat has a 10A contact rating. Can I use it to switch an external contactor?

A: You can, but that’s a modification. The thermostat’s contact rating is 10A, so it can switch an external contactor if you need to control a larger heater. But the AHM2’s built-in 50W heater is sufficient for its design. If you need more heat, you’d be better off with a separate cabinet heater. The AHM2’s thermostat is already in place—you could use it to control a larger heater, but we haven’t tested that configuration.

Q: Does the heater run when the chassis is powered on and the cabinet is warm?

A: No. The thermostat senses the internal temperature. If the cabinet is above 5°C, the heater is off. It only runs when the chassis internal temperature drops below 5°C. In a normal room-temperature environment, you’ll never see the heater turn on. The heater is for cold or variable-temperature environments, not for normal indoor use.

A-B 1756-L61
A-B 1756-L62
SST 5136-DNP-PCI
ABB DSTA180