Struggling with insulated consumer units and information on power dissipation

Question

I am quoting for a new consumer unit to go in to a domestic garage. Supplies 3 circuits in the garage and a couple of circuits to other outbuildings. 
 Especially with the recent guidance on metallic consumer units outside I have been leaning towards using a plastic consumer unit, then comes the challenge. I don't think anyone still builds populated consumer units for more than 4 ways. So then I look at building my own and power dissipation, very little information available from what I can see, the only company providing data is MCG at 1a very low 11W. The best I can find is that some enclosures state then are ok for say 63A, no idea what the assumed heat dissipation is. Also heat a dead end when looking for heat dissipation from RCBO's, I remember in the past seeing 12 to 15w at full load. So I seam to be left with a choice of putting a metal board in and hope it doesn't suffer from condensation, or puta plastic one in and hope it doesn't over heat. I could also put a metal board in a plastic enclosure, a bit less risk with heat. I could probably just use any plastic din rail enclosure and not have an issues, but frustrating this is so difficult. Thoughts?

Gary Jones · Answer

I agree much better to stick with what BS7671 states and use metal CU. The product below would be ideal and will not rust. 
 FuseBox F100GRA Garage Consumer Unit - The FuseBox F100GRA Garage Consumer Unit is a popular choice for residential garages due to its durability, compact design, and excellent safety features. 
 Key features of this consumer unit include: 
 
 Design - The FuseBox F100GRA is a metal consumer unit constructed from high-quality steel, ensuring durability and protection against impact and environmental conditions. It is designed to accommodate various electrical circuits with up to ten usable ways, providing flexibility for connecting multiple devices and appliances.

Gary Jones · Answer

Dear Andy, 
 Thank you for your response and for highlighting your perspective on BS 7671 and the considerations for consumer units in garages. 
 I appreciate your point about the specific application of Regulation 421.1.201 to domestic (household) situations, which might not explicitly include detached garages. I also acknowledge that condensation inside a consumer unit (CU) can pose a risk to delicate components such as RCBOs, potentially leading to greater risks to human life, especially in a TT system. 
 To address these concerns, it's essential to consider the specific environmental conditions of each installation site. While metal consumer units, like the FuseBox F100GRA, offer durability and fire reduction benefits, it is crucial to ensure they are suitable for the given environment. 
 Potential Solutions:

Sealing and Insulation: Consider applying additional seals or insulation to the metal CU to mitigate the risk of condensation. This could help protect the internal components from damp air.

Alternatives: Explore alternative consumer units that are designed to withstand damp environments. For instance, the FuseBox A65 series might be a viable option, though it's essential to confirm whether it is molded plastic or die-cast metal.

Environmental Assessment: Conduct a thorough assessment of the garage environment to determine the best-suited materials for the CU. In some cases, a high-quality plastic CU with appropriate fire retardants might be a better choice.

Ultimately, the goal is to ensure safety and compliance with BS 7671 while considering the specific conditions of each installation site. 
 Thank you for considering my perspective. I hope this information is helpful, and I am open to further discussion on this matter. 
 Best regards, Gary Qualified JIB Technician

Gary Jones · Answer

Hi Alan,
 
 Thank you for the ongoing discussion and for sharing your insights. To clarify the concerns regarding consumer units in domestic garages and compliance with BS 7671, I&rsquo;d like to point out an example of a product that aligns perfectly with these requirements. 
 
 The Schneider Easy9+ Garage Consumer Unit (EZ9EGARAGE63) is an all-metal unit specifically designed for environments like garages. It complies fully with BS 7671, including Regulation 421.1.201 regarding non-combustible enclosures. In addition, it offers: 
 
 Fire Resistance: 
 The metallic enclosure ensures compliance with the fire safety requirements outlined in BS 7671. 
 
 Durability and Protection: 
 It features an IP55 rating, providing resistance to dust and water ingress, making it suitable for damp environments commonly found in garages. 
 
 Enhanced Safety: 
 Equipped with a 63A 30mA RCD incomer and dedicated MCBs for lighting and power circuits, this unit enhances the overall safety of the installation. 
 
 This demonstrates that compliant, durable, and fire-resistant consumer units are readily available for domestic garage applications. Using such a product not only ensures adherence to regulatory standards but also significantly reduces the risk of fire and enhances safety for the property and its occupants. 
 
 I trust this example will help reinforce the importance of selecting appropriate equipment for specific environments, in line with the guidance provided by BS 7671. If there are any further points to clarify, I&rsquo;m happy to discuss them. 
 
 Best regards, 
 
 Gary Jones JIB Technician

Struggling with insulated consumer units and information on power dissipation

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