The Heating Element,electrical,immer, cataloged under National Stock Number 4520-00-901-3690, is classified within Federal Supply Class 4520 (Space and Water Heating Equipment) of the Plumbing, Heating, and Waste Disposal group. The manufacturer of record is Chromalox Inc Dba Chromalox Precision Heat and Control, Inc. Government technical data includes 19 specifications, cited from the U.S. Government catalog. The record lists 2 manufacturer part numbers for this item, enabling identification through both NSN and commercial part number lookups. 3 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog. 1 item shares a part number with this NSN in the catalog (possible match — not a government interchangeability claim). Current acquisition status: Active.
| Parameter | Value |
|---|---|
| NSN | 4520-00-901-3690 |
| Primary Part Number | 139520 |
| Item Name | Heating Element,electrical,immer |
| FSC / FSG | 4520 / 45 — Space and Water Heating Equipment |
| Manufacturer | Chromalox Inc Dba Chromalox Precision Heat and Control, Inc |
| Status | ACTIVE |
| Terminal Quantity | 4 |
| Length | 7.875 INCHES NOMINAL IN |
| Voltage in Volts and Current Type | 240.0 AC SINGLE VOLTAGE |
| Body Style | TUBULAR, SCREW TYPE |
| Maximum Wattage Rating in Watts | 2000.0 SINGLE VOLTAGE |
| Mounting Facility Length | 0.500 INCHES NOMINAL IN |
| Element Connection Style | TERMINAL SCREW |
| Effective Heating Length | 7.875 INCHES NOMINAL IN |
| Terminal Box Environmental Protection | STANDARD |
| Mounting Method Style | SCREW PLUG OR BUSHING TYPE MOUNTING FACILITY |
| Nominal Thread Size | 2.000 INCHES MOUNTING FACILITY IN |
| Heat Quantity | 1 |
| Watt Density Rating | 47.0 PER SQUARE INCH SINGLE VOLTAGE |
| Element Radiation Spectrum | NONINFRARED |
| Material | COPPER ALLOY SHEATH |
| Material | NICKEL AND CHROMIUM RESISTANCE WIRE |
| Thread Series Designator | NPT MOUNTING FACILITY |
| Thread Quantity | 11.5 PER INCH MOUNTING FACILITY |
| Element Quantity | 2 |
| Acquisition Status | ACTIVE |
| DEMIL Code | DEMIL A — No Demilitarization Required |
| Hazard | No hazard code in the DLA record (HMIC N) |
| Criticality Code | X |
| Part Number | Manufacturer |
|---|---|
| MT-220A-240V | Chromalox Inc Dba Chromalox Precision Heat and Control, Inc (USA) |
| 139520 PRIMARY | Chromalox Inc Dba Chromalox Precision Heat and Control, Inc (USA) |
| Reference | Meaning |
|---|---|
| BC21841 | 5/9 Secondary reference Chromalox Inc Dba Chromalox Precision Heat and Control, Inc |
| J2-15012 | 5/9 Secondary reference Chromalox Inc Dba Chromalox Precision Heat and Control, Inc |
| MT2203XX250VDC | 5/9 Secondary reference Chromalox Inc Dba Chromalox Precision Heat and Control, Inc |
NSN 4520-00-901-3690 is a Heating Element,electrical,immer, manufactured by Chromalox Inc Dba Chromalox Precision Heat and Control, Inc, classified under FSC 4520, Space and Water Heating Equipment. Status: active.
NSN 4520-00-901-3690 has 2 manufacturer part numbers on file: MT-220A-240V (Chromalox Inc Dba Chromalox Precision Heat and Control, Inc), 139520 (Chromalox Inc Dba Chromalox Precision Heat and Control, Inc).
1 possible match (shared part number, not a government interchangeability claim): 5998-01-443-6350. Verify interchangeability with system specifications before substitution.
Key specifications for 139520: Terminal Quantity: 4; Length: 7.875 INCHES NOMINAL IN; Voltage in Volts and Current Type: 240.0 AC SINGLE VOLTAGE; Body Style: TUBULAR, SCREW TYPE. 19 specifications are documented in the U.S. Government catalog.
No hazard code in the DLA record (HMIC N). Hazard information on this page is shown exactly as it appears in the DLA record.
U.S. Government catalog: edition PUBLOGDVD v12.0.0 (OCT 2026), edition date 2026-10-01, retrieved 2026-10-16.
U.S. Government catalog: edition PUBLOGDVD v12.0.0 (OCT 2026), edition date 2026-10-01, retrieved 2026-10-18.