Product Overview
GE 29701 Constant Color Mini CMH 70W G8.5 Lamp - 4200K Cool White - 90 CRI
The GE 29701 Constant Color Mini CMH is a compact 70W Ceramic Metal Halide lamp featuring a G8.5 bi-pin base and exceptional 90 CRI color rendering. Delivering 6,200 lumens of crisp 4200K cool white light, this "Mini" CMH is ideal for high-end retail display lighting, museum applications, and architectural accent fixtures where space is limited. With 15,000-hour rated life and ANSI C139 compatibility, it offers superior color stability in a compact T4.5/T6 format.
Technical Specifications - GE 29701 Mini CMH
Electrical
| Manufacturer Part Number | 29701 |
|---|---|
| Wattage | 70 Watts |
| Lamp Operating Voltage | 90 Volts AC (Nominal) |
| Base Type | G8.5 Bi-Pin (Double-Ended Ceramic) - 8.5mm spacing |
| ANSI Ballast Code | C139 / M139 (Pulse Start) |
| Starting Pulse | 3.5-5.0 kV (Provided by ballast) |
Photometric Performance
| Color Temperature | 4200K (Cool White / Neutral) |
|---|---|
| Color Rendering Index (CRI) | 90 (Excellent - Museum Quality) |
| Initial Lumens | 6,200 lm |
| Efficacy | 88.6 Lumens per Watt |
| Lumen Maintenance | 90% at 40% of rated life |
| Rated Life (L70) | 15,000 Hours |
Physical & Thermal
| Designation | TC (Tubular Compact) / Mini CMH |
|---|---|
| Tubular Size | T4.5 or T6 (14.2mm diameter) |
| Maximum Overall Length (MOL) | 85.6mm (3.37 inches) |
| Bulb Diameter | 14.2mm (0.56 inches) |
| Burning Position | Universal (Any orientation ±90°) |
| Ambient Operating Range | -40°C to +55°C (-40°F to +131°F) |
Compatible Ballast Systems - ANSI C139 / M139
Important: This 70W Mini CMH typically uses ANSI M139 ballasts (standard for 70W CMH). The "C139" marking indicates Ceramic Metal Halide compatibility. Verify your ballast is rated for 70W pulse-start CMH (G8.5 base).
Ballast Requirements:
- Electronic Ballasts: GE GEMH70 series, Philips Advance Xitanium 70W CMH, Osram PT-FIT 70
- Magnetic Ballasts: CWA (Constant Wattage Autotransformer) types rated M139/C139
- Input Voltage: 120V, 208V, 240V, or 277V (match ballast to supply)
- Socket: G8.5 ceramic bi-pin rated for high temperature (250°C+)
4200K Cool White Applications
The 4200K color temperature provides neutral-cool white light that enhances contrast and alertness:
3000K (Warm White)
Cozy, yellowish
Best for: Restaurants, homes, hospitality
4200K (Cool White) ← This Lamp
Neutral, crisp
Best for: Retail, offices, museums, task lighting
5600K (Daylight)
Blue-white, harsh
Best for: Industrial, security only
Why 4200K? This "cool white" temperature provides better color discrimination than warm white (3000K) without the clinical harshness of 5000K+ daylight. Ideal for displaying merchandise, artwork, and architectural details where color accuracy and visual clarity are important.
Mini CMH vs Traditional HID
| Specification | GE 70W Mini CMH | 75W Halogen PAR | 100W Metal Halide |
|---|---|---|---|
| Wattage | 70W | 75W | 100W |
| Lumens | 6,200 lm | 1,100 lm | 8,500 lm |
| Efficacy | 88 LPW | 14 LPW | 85 LPW |
| CRI | 90 (Excellent) | 100 (Perfect) | 65 (Fair) |
| Size | Compact (85mm) | Large (PAR38) | Large (E26/E39) |
| Color Stability | Excellent (Constant Color) | Perfect | Poor (shifts to green) |
Advantage: This GE Mini CMH fits smaller fixtures than standard MH while providing 90 CRI color quality impossible with standard metal halide.
Professional Applications for Mini CMH G8.5
High-End Retail
- Boutique Track Lighting: Compact G8.5 fits small gimbals
- Jewelry Displays: 90 CRI reveals true gem colors
- Fashion Merchandising: 4200K neutral white shows fabric true colors
- Cosmetic Counters: Excellent skin tone rendering
- Art Galleries: 90 CRI suitable for color-critical exhibitions
Commercial & Office
- Reception Downlights: Clean 4200K projects professionalism
- Conference Rooms: High CRI for accurate color presentation
- Medical Office: Task lighting with excellent color rendering
- Architectural Accent: Compact size for cove lighting
Museums & Galleries
- Artifact Illumination: 90 CRI with UV-filtered enclosed fixtures
- Sculpture Lighting: Point source for precise beam control
- Temporary Exhibits: 15,000-hour life covers exhibition runs
- Display Cases: Compact size fits integrated casework lighting
Compatible Replacements & Industry Equivalents
This GE 29701 (G8.5 base, 70W, 4200K) is electrically compatible with:
| Brand | Part Number | Notes |
|---|---|---|
| Philips MasterColor | CDM-TC 70W/942 G8.5 | 4200K (942), 90 CRI |
| Osram Powerstar | HCI-TC 70/942 NDL G8.5 | Neutral Deluxe, 4200K |
| Sylvania Metalarc | MC70TC/U/G8.5/942 | Cool white variant |
| Ushio | UM70/G8.5/TC/942 | 85mm length compatible |
Note: All listed lamps use G8.5 bi-pin base (8.5mm spacing, NOT G12). Verify fixture socket before ordering.
Safety Information & Certifications
⚠️ UV Radiation Warning
- Shortwave UV emission: Can cause serious skin burns and eye inflammation
- Enclosed fixtures mandatory: Must meet UL 1573 (Stage/Studio) or UL 1598 (Luminaires)
- G8.5 base: Double-ended design requires proper contact in ceramic socket
- Immediate replacement: Required if outer envelope damaged
- Auto-extinguish recommended: For areas with human exposure
? Operating Safety
- High pressure operation - risk of hot quartz rupture
- Allow 15-minute cool-down before handling
- Use ceramic G8.5 sockets only (plastic will melt)
- Verify ballast compatibility before installation
- Minimum 3-inch clearance from combustible materials
? Certifications
- cULus Listed: File #E328950
- CE Marked: European compliance
- RoHS 2: Directive 2015/863/EU compliant (reduced mercury)
- FCC Part 15: Subpart B compliant (EMI/RFI)
- California Title 20: Appliance efficiency compliant
Frequently Asked Questions
What is a "Mini" CMH lamp?
Mini CMH (also called TC or Tubular Compact) refers to the G8.5 base format with a T4.5/T6 tubular shape (14.2mm diameter, 85mm length). Compared to standard E26/E39 base CMH lamps, Mini CMH fits compact track heads, small downlights, and display fixtures. This GE 29701 packs 70W and 6,200 lumens into a lamp smaller than a halogen PAR30.
What is the difference between G8.5 and G12 bases?
G8.5 (this lamp) has 8.5mm pin spacing and is used for 35W-150W Mini/TC CMH lamps with compact T4.5/T6 tubular shape. G12 has 12mm spacing and is typically for larger T6 tubular CMH (35W-70W). G8.5 is more compact and fits smaller fixtures. They are not interchangeable - verify your socket has 8.5mm spacing between pins.
Is 4200K too cool for retail lighting?
4200K is ideal for retail, especially clothing, jewelry, and merchandise where color accuracy matters. While 3000K is "cozy" and better for restaurants, 4200K provides neutral white light that shows true colors without the yellow cast of warm white. It's also preferred for offices and task lighting where alertness is desired. However, for high-end hospitality or residential, 3000K might be preferred.
What is the difference between ANSI C139 and M139?
C139 specifically designates Ceramic Metal Halide (CMH) compatibility, while M139 is the general ballast standard for 70W pulse-start metal halide systems. Modern electronic ballasts for 70W CMH are typically labeled both C139 and M139. If your ballast is marked only M139 (older magnetic type), verify it supports ceramic metal halide lamps - some early M139 ballasts were designed for quartz MH only.
Can I use a 70W Mini CMH in a 35W fixture?
No. This 70W lamp requires approximately twice the operating current of a 35W lamp. Using in a 35W ballast (M130/C130) will result in insufficient power, poor color, and shortened life. Conversely, a 35W lamp in a 70W ballast (M139/C139) will be overdriven and fail catastrophically. Always match lamp wattage to ballast rating. The G8.5 base is physically similar for 35W and 70W, so verify wattage markings carefully.
