Understanding Indoor vs Outdoor LVAC Boards
Despite their similar electrical function, indoor and outdoor LVAC boards have distinct design characteristics, environmental requirements, and regulatory considerations.
Indoor boards are, well..… indoors; meaning they are housed within a building or enclosure. Outdoor boards, on the other hand, are self-contained entities, fundamentally different in both fabric and design, and directly exposed to the elements.
Treating them accordingly in terms of environmental control and expectations will save you headaches in the future. A good rule of thumb is to ensure adequate heating, dehumidification, and cooling (if necessary) from the start. Choosing the right solution and allowing sufficient space during the design phase will save you from costly replacements down the line.
By all means, refer to the limits set in BS EN 61439, but don’t rely on them as everyday running conditions. Weather can be unpredictable, swinging between extremes, and these fluctuations can accelerate degradation if the environment isn’t properly managed.
Indoor LVAC Boards: Built for Controlled Environments
Key Characteristics
- Lower IP Ratings: Often rated IP31 or IP42, sufficient for protecting against solid objects and limited moisture but not suited for outdoor conditions.
- Ventilation Considerations: Designed with natural or forced ventilation to dissipate heat within enclosed spaces.
- Material Construction: Standard sheet steel or aluminum enclosures without additional weatherproofing. Standard sheet steel being the most widely used offering.
- Environmental Limitations: Indoor boards follow BS EN 61439-1 temperature limits, typically designed for an ambient temperature of -5°C to 40°C (Clause 7.1.1) with controlled humidity levels.
- Humidity Control: Indoor LVAC boards are designed to operate in environments with relative humidity levels up to 50% at 40°C and up to 90% at 20°C (Clause 7.1.2). Consistently high humidity levels can lead to condensation and corrosion if not properly managed.
External Location Considerations
An indoor LVAC board can be used in an external location if an appropriately designed structure is placed over it to regulate the environment effectively. However, simply constructing a building over an LVAC board does not automatically ensure proper environmental control. Factors such as ventilation, temperature regulation, moisture ingress, and corrosion protection must be actively managed to maintain compliance and functionality.
Preferred Solution for Longevity
An indoor LVAC board housed within a well-designed building is generally the preferred solution due to its enhanced protection, reduced maintenance, and extended lifespan. By maintaining stable environmental conditions, these setups significantly reduce the risk of electrical failure, corrosion, and overheating, ultimately resulting in lower maintenance costs and greater reliability over time.
Controlled Environment vs. Maximum Limits
While BS EN 61439 defines operational limits for temperature and humidity, relying on these maximum values is not a realistic long-term strategy. A properly controlled environment should maintain conditions well below these thresholds to maximise the lifespan and reliability of the switchgear. Over time, operating at or near maximum limits can accelerate component degradation, insulation failure, and condensation issues.
Outdoor LVAC Boards: Self-Standing and Built for the Elements
Key Characteristics
- Higher IP Ratings: Often IP54, IP55, or IP66, ensuring protection from dust, rain, and other environmental factors.
- Self-Standing and Fully Sealed: Designed to function independently without the need for an external enclosure.
- Temperature and Humidity Resilience: Built to withstand greater temperature variations, often rated for ambient conditions up to 50°C (Clause 7.1.1) or extreme cold environments. Outdoor LVAC boards can typically operate in humidity levels up to 100% at 25°C (Clause 7.1.2.2) with appropriate condensation prevention measures.
- Corrosion-Resistant Materials: Typically constructed from stainless steel, aluminum, or GRP (Glass Reinforced Plastic) with additional coatings for UV and chemical resistance.
- Integrated Drainage and Ventilation: Uses louvered vents, condensation management systems, and heat dissipation technology to prevent internal moisture buildup.
Maintenance and Cost Considerations
Due to constant exposure to UV radiation, rain, and temperature fluctuations, outdoor LVAC boards require frequent inspections and preventative maintenance to ensure continued functionality. The cost of maintenance over time can be significantly higher than an indoor board housed in a protective building.
Outdoor LVAC boards are specialised solutions intended for locations where a protective building is not feasible. Their rugged construction, high IP ratings, and environmental resilience make them more expensive than their indoor counterparts, with higher operational costs due to increased maintenance requirements.
BS EN 61439 Compliance: Indoor vs. Outdoor Parameters
The BS EN 61439 standard outlines specific environmental conditions that LVAC boards must comply with, depending on whether they are designed for indoor or outdoor use. These parameters are clearly defined to avoid ambiguity:
- Temperature Range:
- Indoor: -5°C to 40°C (Clause 7.1.1)
- Outdoor: -25°C to 50°C (Clause 7.1.1)
- Humidity Resistance:
- Indoor: 50% at 40°C, 90% at 20°C (Clause 7.1.2.1)
- Outdoor: 100% at 25°C (Clause 7.1.2.2)
- Maximum Internal Temperature Threshold:
- Indoor: 50°C before operational risk (Clause 7.1.1)
- Outdoor: 60°C with additional cooling measures (Clause 7.1.1)
- Acceptable Continuous Operating Temperature:
- Indoor: ≤ 40°C (recommended lower for longevity) (Clause 7.1.1, 9.2)
- Outdoor: ≤ 50°C with external cooling solutions (Clause 7.1.1, 9.2)
Importance of Temperature and Humidity Management
While 40°C (Indoor) and 50°C (Outdoor) is the maximum operational temperature under BS EN 61439, it is important to note that maintaining a lower temperature significantly extends the lifespan of the switchgear. Excessive heat accelerates the degradation of insulation, wiring, and mechanical components, leading to reduced reliability and increased maintenance requirements.
Similarly, high humidity levels can contribute to moisture condensation, corrosion, and insulation breakdown, especially if adequate ventilation is not in place. For best long-term reliability, indoor LVAC boards should be maintained below their maximum humidity and temperature thresholds to avoid unnecessary wear and premature failure.
Wrapping It Up
Understanding the difference between indoor and outdoor LVAC boards is crucial to ensuring safety, compliance, and longevity in any electrical installation. For most applications, an indoor LVAC board housed within a properly designed building is the superior choice, offering greater protection, lower maintenance, and longer service life.
Outdoor LVAC boards, while rugged and specialised, require higher investment and ongoing upkeep, making them suitable only for niche applications in extreme conditions.
If you’re still unsure about the best solution for your project, consult with an LVAC specialist to determine the most suitable option based on your environmental conditions and operational needs.
Disclaimer:
The information provided on this site is for general informational purposes only and may not reflect the most current regulations or standards. Legislation, industry guidelines, and best practices can change over time, and it is the user’s responsibility to research and ensure compliance with the latest requirements for their specific situation. Always consult a qualified professional for advice tailored to your project or application.
