If you are researching the OSRAM HQI-T 400W/N, you are likely looking for more than just a basic lamp description. You probably need to know whether this 400W metal halide lamp is compatible with your fixture, how it performs in real-world industrial lighting, and whether it is still a practical choice today. The OSRAM HQI-T 400W/N is a quartz metal-halide high-intensity discharge lamp designed for enclosed fixtures in demanding spaces such as industrial halls, sports venues, and outdoor floodlighting installations.
What makes the OSRAM HQI-T 400W/N stand out is its combination of high output, neutral-white light, E40 mogul base, and built-in UV-block filter. In one product, you get a lamp intended for large-area illumination where brightness, fixture compatibility, and dependable performance matter. At the same time, the OSRAM HQI-T 400W/N is very much a traditional HID solution, which means it comes with the usual considerations: warm-up time, magnetic control gear, external ignition, non-dimmable operation, and no instant hot restart.
In this guide, we will break down the OSRAM HQI-T 400W/N in practical terms. We will cover its design, electrical characteristics, optical output, installation requirements, ballast and ignitor compatibility, best-use scenarios, limitations, and how it compares with similar 400W metal halide lamps. By the end, you should have a clearer picture of whether the OSRAM HQI-T 400W/N is the right fit for your application.
What Is the OSRAM HQI-T 400W/N?
The OSRAM HQI-T 400W/N is part of OSRAM’s POWERSTAR HQI-T family, a range of tubular quartz metal-halide lamps intended for enclosed luminaires. It is a single-ended lamp with an E40 mogul screw base and is commonly identified by the full designation OSRAM Powerstar HQI-T 400W Neutral White (N) or part number HQI-T 400W/N/SI. The lamp is designed for installations where a strong, high-intensity light source is needed across large spaces rather than for decorative or small-scale lighting.
At its core, the OSRAM HQI-T 400W/N is built for performance. It operates at a nominal power of 400 watts and produces a neutral-white light that typically sits around 4100K. That colour temperature makes it especially useful in environments where operators want a clean, balanced white light rather than the warmer appearance of some other HID lamps. The output profile of the OSRAM HQI-T 400W/N suits industrial and sports settings because it supports visibility without leaning too yellow.
Another defining feature of the OSRAM HQI-T 400W/N is its tubular quartz envelope and UV-absorbing filter. The UV-blocking construction is an important safety feature because the lamp is still intended only for enclosed fixtures. In other words, even though the OSRAM HQI-T 400W/N helps suppress ultraviolet radiation well below relevant safety limits, it is not a lamp meant for open, exposed operation. Users need a luminaire designed specifically for HID service.
The lamp also belongs to an older but still respected category of lighting technology. Unlike LED products that often integrate electronics more seamlessly, the OSRAM HQI-T 400W/N relies on conventional electromagnetic control gear, an ignitor, and proper system matching. This is one reason why engineers and maintenance teams looking at the OSRAM HQI-T 400W/N usually want the full specification picture before purchasing.
OSRAM HQI-T 400W/N Key Technical Specifications
From a specification standpoint, the OSRAM HQI-T 400W/N is a high-output 400W HID lamp with a strong balance of lumen performance, neutral-white colour, and industrial-grade construction. Initial luminous flux is commonly listed around 31,000 lumens, though some sources cited in the summary place it as high as 40,000 lumens under favourable conditions. That means the OSRAM HQI-T 400W/N is designed to deliver substantial brightness over wide areas.
The luminous efficacy of the OSRAM HQI-T 400W/N is generally around 82 lumens per watt at start, with older or alternate listings noting values that can approach roughly 90 lumens per watt depending on the specific version or test conditions. Colour temperature is typically around 4100K, giving the lamp its neutral-white appearance. Color Rendering Index (CRI) is moderate rather than exceptional, with a CRI usually in the range of Ra 62 to 67. For industrial, warehouse, and stadium lighting, that level of colour rendering is often acceptable, though it is not comparable to many modern LED alternatives.
Physically, the OSRAM HQI-T 400W/N uses a single-ended tubular design. The lamp is about 285 mm long and about 57 mm in diameter, with a light centre length of around 160 mm. It uses an E40 mogul base, which is common for higher-wattage HID lamps in industrial installations. The OSRAM HQI-T 400W/N is relatively light for its output class, but the operating conditions are serious: outer bulb temperatures can become very high, which is why fixture design and enclosure requirements matter.
Rated life for the OSRAM HQI-T 400W/N is typically around 10,000 hours, with some figures extending to around 12,000 hours depending on the source and operating conditions. Lumen maintenance declines over time, as expected with metal halide technology. The summary notes that light output can fall significantly as the lamp ages, which means facilities using the OSRAM HQI-T 400W/N often replace lamps in groups rather than waiting for full failure.
The lamp also contains mercury, roughly 55 mg, which affects handling, recycling, and disposal. This is an important point for anyone specifying the OSRAM HQI-T 400W/N in a facility with environmental compliance requirements.
How the OSRAM HQI-T 400W/N Performs in Real Installations
The practical appeal of the OSRAM HQI-T 400W/N lies in its ability to flood large spaces with a strong, usable white light. In warehouses, industrial halls, sports arenas, and outdoor floodlighting systems, the lamp can provide the kind of punch that older HID installations were designed around. The OSRAM HQI-T 400W/N emits light in all directions as a bare lamp, so the final beam control depends heavily on the reflector and fixture design.
That is worth emphasising because people sometimes assess the OSRAM HQI-T 400W/N as though it were a standalone beam-controlled source. It is not. The lamp is omnidirectional in its bare form, and the optical performance of the full luminaire depends on the housing, reflector geometry, and installation height. In a well-matched enclosure, the OSRAM HQI-T 400W/N can support broad-area illumination efficiently and consistently.
Warm-up behaviour is another practical consideration. The OSRAM HQI-T 400W/N does not reach full brightness instantly. After cold ignition, it usually takes a few minutes to approach full output and colour stability. The summary indicates that the lamp reaches most of its usable light within about three to five minutes. That delay is normal for metal halide technology, but it matters in environments where instant-on lighting is expected.
The OSRAM HQI-T 400W/N also cannot be hot-restarted immediately after power interruption. Once the lamp shuts off, it needs a cooldown period before restrike. In some use cases, that is a manageable trade-off. In others, especially where uninterrupted lighting recovery matters, the limitation may be more significant. Anyone evaluating the OSRAM HQI-T 400W/N for critical operations should account for this behaviour in their lighting design.
As the lamp ages, the OSRAM HQI-T 400W/N experiences lumen depreciation, colour shift, and possible flicker near end of life. These are normal HID ageing characteristics, and they help explain why preventive maintenance is so important.
OSRAM HQI-T 400W/N Ballast, Ignitor, and Fixture Compatibility
One of the most important parts of specifying the OSRAM HQI-T 400W/N is understanding that it is not a simple screw-in replacement in the everyday consumer sense. Yes, it has an E40 mogul base, but the system compatibility requirements go far beyond the socket. The OSRAM HQI-T 400W/N needs conventional electromagnetic metal-halide control gear and an appropriate ignitor.
The summary notes that the OSRAM HQI-T 400W/N typically operates at around 120 volts and about 3.4 amps at rated conditions, with total system power reaching roughly 440 watts when ballast losses are included. It also requires an ignition pulse in the range of about 0.75 to 1.3 kVp. That point matters because using the wrong ignitor can damage the system or create unsafe operating conditions. The OSRAM HQI-T 400W/N should not be paired casually with just any HID accessory.
In practical terms, the OSRAM HQI-T 400W/N is intended for magnetic ballast operation with an external or integrated ignitor that matches the lamp’s needs. The summary also notes that it is not meant for dimming and that an electronic HID ballast is not the standard arrangement for this model. That means maintenance teams working with the OSRAM HQI-T 400W/N should verify ballast current, ignitor characteristics, power factor correction, and wiring layout before installation.
A recommended power factor correction capacitor is also mentioned in the summary, with about 45 µF at 50 Hz helping bring power factor near 0.9. Without appropriate compensation, the OSRAM HQI-T 400W/N system may run with lower power factor, which can matter in larger facilities concerned with electrical efficiency and system quality.
Fixture compatibility is equally critical. The OSRAM HQI-T 400W/N is designed for enclosed luminaires only. The lamp runs hot, and the luminaire must be rated to handle HID temperatures and contain the lamp safely. A heavy-duty ceramic E40 socket is recommended, and sufficient clearance and ventilation inside the enclosure are necessary. In short, the OSRAM HQI-T 400W/N belongs in a properly engineered fixture, not in a casual retrofit situation without system verification.
Where the OSRAM HQI-T 400W/N Works Best
The OSRAM HQI-T 400W/N is best suited to large-area applications where high-output white light is needed and where the fixture system has already been designed around HID technology. Common examples include industrial halls, warehouses, loading bays, sports facilities, stadium-related spaces, and outdoor floodlighting systems that use enclosed luminaires.
In these settings, the OSRAM HQI-T 400W/N makes sense because its lumen package is substantial enough to support high mounting heights and broad coverage. The neutral-white appearance also works well in places where users want a cleaner, more balanced look than the warmer light produced by some alternative HID sources. For facility operators who still maintain legacy HID infrastructure, the OSRAM HQI-T 400W/N can remain a practical lamp choice.
Another strength of the OSRAM HQI-T 400W/N is that it fits applications where ruggedness and proven lamp technology are valued. Many industrial systems were engineered around metal halide lamps long before LED retrofits became common. In those environments, replacing like-for-like with the OSRAM HQI-T 400W/N may be more straightforward than redesigning the entire lighting system immediately.
That said, the OSRAM HQI-T 400W/N is not ideal for every project. It is not a good match for small luminaires, open lamp holders, or spaces where instant restrike is essential. It is also less attractive in situations where energy efficiency, low maintenance, and higher colour rendering are the main priorities. The best use case for the OSRAM HQI-T 400W/N is still a properly enclosed large-area fixture where its output and operating profile align with the application.
For buyers, that means the OSRAM HQI-T 400W/N should be evaluated as a system component rather than a generic lamp. The right question is not only “Will it fit?” but also “Was the luminaire designed for this kind of lamp, ballast, and ignition behaviour?”
Advantages and Limitations of the OSRAM HQI-T 400W/N
Like many legacy HID products, the OSRAM HQI-T 400W/N offers strong benefits in the right environment while also carrying limitations that are impossible to ignore. On the advantage side, the lamp delivers high output for its class, offers a useful neutral-white colour tone, and has a built-in UV-block filter that improves safety when used as intended. For operators maintaining existing HID systems, the OSRAM HQI-T 400W/N can be a dependable continuation of a known lighting platform.
The OSRAM HQI-T 400W/N also benefits from a familiar infrastructure base. Many facilities already understand how to service magnetic ballasts, ignitors, E40 sockets, and enclosed HID luminaires. When a site already has those systems in place, continuing with the OSRAM HQI-T 400W/N may be operationally simpler than making an immediate jump to an entirely different technology.
However, the limitations of the OSRAM HQI-T 400W/N are equally important. The lamp is not dimmable, cannot be hot-restarted immediately, and requires warm-up time after ignition. It contains mercury, runs very hot, and experiences lumen depreciation and colour shift over time. Compared with modern LED lighting, the OSRAM HQI-T 400W/N also falls short in areas such as maintenance intervals, controllability, and often overall system efficiency.
Cost can also be a factor. According to the summary, pricing can range widely, from surplus or special-sale listings at low prices to several hundred dollars per lamp through professional supply channels. That means the OSRAM HQI-T 400W/N is not always a budget choice, especially when sourced in markets where supply is limited or lead times are long.
Ultimately, the OSRAM HQI-T 400W/N remains most attractive where legacy system continuity matters more than adopting the latest lighting controls or lowest-maintenance solution.
OSRAM HQI-T 400W/N vs Comparable 400W Metal Halide Lamps
The summary compares the OSRAM HQI-T 400W/N with similar 400W tubular metal halide lamps, including the Philips HPI-T Plus 400W/645 and a GE 400W Whitelux model. That comparison helps position the OSRAM HQI-T 400W/N in the broader HID market.
Against these alternatives, the OSRAM HQI-T 400W/N offers a lumen output in the low-30,000 range, with some sources placing it higher. Philips and GE alternatives in the comparison are listed with somewhat higher lumen values and, in some cases, longer life or higher CRI. For example, the GE comparison entry shows warmer colour and higher CRI, while the Philips entry shows a cooler colour temperature and longer rated life. This means the OSRAM HQI-T 400W/N is competitive, but not necessarily dominant in every metric.
Where the OSRAM HQI-T 400W/N holds its place is in its neutral-white balance, established brand recognition, compatibility with traditional magnetic control gear, and its fit within OSRAM’s long-running POWERSTAR HQI-T family. For users already committed to OSRAM-based systems, the OSRAM HQI-T 400W/N may be the most convenient and technically coherent choice.
It is also worth noting that HID comparisons should never be reduced to lumen numbers alone. In actual service, the OSRAM HQI-T 400W/N must be judged by fixture compatibility, light distribution, colour preference, maintenance strategy, and sourcing conditions. A lamp that looks slightly stronger on paper is not necessarily the better choice if the installed system was designed specifically around the OSRAM HQI-T 400W/N operating profile.
So while there are comparable 400W metal halide options on the market, the OSRAM HQI-T 400W/N still has clear relevance in existing lighting ecosystems that value continuity and predictable behaviour.
Installation, Safety, and Maintenance Tips for OSRAM HQI-T 400W/N
Installing the OSRAM HQI-T 400W/N correctly is essential to both performance and safety. First, power should always be disconnected before replacing the lamp. Because the OSRAM HQI-T 400W/N uses a quartz envelope, it should be handled by the base or with clean gloves to avoid transferring oils onto the surface. Contamination on the lamp envelope can affect long-term reliability under high heat.
The OSRAM HQI-T 400W/N should be mounted only in a compatible enclosed luminaire and with the proper orientation guidance from the product documentation. The summary indicates universal operating orientation, though horizontal positions are often treated as a reference point. Installers should still follow the equipment manufacturer’s instructions for the exact fitting and enclosure.
Since the OSRAM HQI-T 400W/N cannot hot-restart immediately, maintenance staff should expect a cooldown window after shutdown. They should also replace lamps promptly when flicker, arc instability, or severe lumen loss becomes noticeable. Running the OSRAM HQI-T 400W/N too far past rated life increases the likelihood of unstable behaviour and reduced lighting quality.
From a safety standpoint, the OSRAM HQI-T 400W/N contains mercury and must be disposed of according to local hazardous waste or recycling regulations. Facilities should never treat spent lamps as ordinary general waste. The lamp’s built-in UV filter improves safety, but it does not remove the need for enclosed operation. The OSRAM HQI-T 400W/N is still intended for use only within suitable luminaires that contain the lamp and protect users.
Routine maintenance also matters. Keeping reflectors and enclosure surfaces clean will help the OSRAM HQI-T 400W/N perform closer to its intended output. In multi-lamp systems, group relamping may deliver better consistency than one-at-a-time replacement. That strategy is especially useful where lighting levels must remain uniform across a large facility.
Is the OSRAM HQI-T 400W/N Still Worth Buying?
Whether the OSRAM HQI-T 400W/N is still worth buying depends largely on your existing lighting system and project priorities. If you are maintaining a legacy HID installation designed around 400W metal halide lamps, the OSRAM HQI-T 400W/N can still make strong practical sense. It offers the familiar operating profile, mounting format, output class, and control-gear expectations that many older industrial and sports luminaires were built around.
For that kind of replacement scenario, the OSRAM HQI-T 400W/N is not just a lamp. It is part of an installed ecosystem. Swapping to a different lamp family or to LED may involve fixture replacement, ballast bypass strategies, photometric redesign, and new budgeting considerations. In cases where maintaining the original system is the priority, the OSRAM HQI-T 400W/N remains a relevant option.
On the other hand, buyers planning a new lighting project from scratch may not automatically find the OSRAM HQI-T 400W/N to be the best long-term choice. LED systems now offer advantages in instant-on behaviour, improved controllability, reduced maintenance, and often better overall lifecycle economics. The summary even notes that many LED high-bay and arena fixtures are marketed as replacements for 400W metal halide systems.
So the value of the OSRAM HQI-T 400W/N is context-specific. For existing HID infrastructure, it can be highly appropriate. For new installations, it should be assessed more carefully against current alternatives. The key is to evaluate the OSRAM HQI-T 400W/N not only as a lamp purchase, but as part of a complete lighting strategy.
Frequently Asked Questions About the OSRAM HQI-T 400W/N
Is the OSRAM HQI-T 400W/N dimmable?
No. The OSRAM HQI-T 400W/N is not intended for dimming. It is designed for standard on-off HID operation with the correct conventional control gear. Trying to use the OSRAM HQI-T 400W/N with unsuitable dimming equipment can shorten lamp life, reduce stability, or create performance issues.
Can the OSRAM HQI-T 400W/N be used in an open fixture?
No. The OSRAM HQI-T 400W/N is intended for enclosed fixtures only. Even with a UV-blocking filter, the lamp must be used in a luminaire designed for HID operation and proper containment. Anyone purchasing the OSRAM HQI-T 400W/N should confirm enclosure suitability before installation.
How bright is the OSRAM HQI-T 400W/N?
The OSRAM HQI-T 400W/N is typically listed around 31,000 lumens, with some cited sources placing the lamp higher under certain conditions. In practical use, the real-world performance of the OSRAM HQI-T 400W/N depends on the reflector, enclosure design, mounting height, and lamp age.
What colour of light does the OSRAM HQI-T 400W/N produce?
The OSRAM HQI-T 400W/N produces a neutral-white light, commonly around 4100K. This gives the lamp a balanced white appearance that works well in industrial and sports environments where clarity and broad-area visibility matter.
Does the OSRAM HQI-T 400W/N need a ballast and ignitor?
Yes. The OSRAM HQI-T 400W/N requires compatible metal-halide control gear and an appropriate ignitor. It is not a direct household-style screw-in lamp even though it uses an E40 mogul base. Proper ballast and ignitor matching are essential for safe operation of the OSRAM HQI-T 400W/N.
Is the OSRAM HQI-T 400W/N a good LED replacement option?
The OSRAM HQI-T 400W/N itself is not an LED replacement. Rather, it is a traditional HID lamp that may remain useful in existing metal halide systems. If a facility is planning an LED conversion, the OSRAM HQI-T 400W/N should be viewed as a maintenance choice for legacy infrastructure, not as a forward-looking LED-style solution.
Related Product Collections
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Final Thoughts on the OSRAM HQI-T 400W/N
The OSRAM HQI-T 400W/N remains a specialised, high-output metal halide lamp built for enclosed industrial and stadium-style lighting applications. Its strengths include solid lumen output, a neutral-white colour appearance, E40 base compatibility, and a design suited to large-area luminaires. Its drawbacks are equally clear: warm-up time, no hot restart, no dimming, mercury content, high operating temperature, and dependence on proper magnetic control gear.
For facilities already using HID infrastructure, the OSRAM HQI-T 400W/N can still be a practical and technically sound replacement when matched with the correct ballast, ignitor, socket, and enclosed fixture. For new projects, it should be weighed against modern alternatives with a full understanding of installation, maintenance, and lifecycle requirements.
If you are considering the OSRAM HQI-T 400W/N for a replacement or procurement decision, the next step is to review the product page carefully, explore the related collections above, and confirm the exact specifications, compatibility details, and current availability before ordering.
