The IET is carrying out some important updates between 17-30 April and all of our websites will be view only. For more information, read this Announcement

Rules and Guidelines
Want to participate in the discussions? Please read our Community Rules and Guidelines. Need some help? Visit Support and Answers.

  • State Suggested Answer
  • Replies 33 replies
  • Helpful Answers 3 Helpful answers
  • Subscribers 39 subscribers
  • Views 1799 views
  • Users 0 members are here
Options
You may also be interested in

Struggling with insulated consumer units and information on power dissipation

Alan B

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?

  • 0 in reply to AJJewsbury

    Hi Andy,

    Thanks again for your detailed input. While I value a healthy and constructive discussion, I’d like to keep this focused on the specific matter at hand. I’ve noticed the conversation has drifted into tangential areas that, while interesting, don’t directly address the core topic of metallic consumer units (CUs) and their compliance in specific environments like detached outbuildings.
    You mentioned that "the primary concern here is ensuring all parts of an electrical installation within the same property adhere to the same safety standards" is patently false. I’d like to clarify: the intention here is not to argue that every room or area follows identical standards, but rather that all parts of the system must meet the relevant safety requirements for their specific environments, as outlined in BS 7671.
    For example:  
    Sections 512.2.1 and 513.1 require electrical equipment to be suitable for external influences, such as dampness or mechanical stresses, which are common considerations in outbuildings.  
    Regulation 421.1.201 mandates the use of non-combustible enclosures for consumer units in domestic premises to enhance fire safety. This is particularly relevant in outbuildings where flammable materials might be stored.  
    Regulation 559.10.1.2 highlights the importance of selecting equipment suitable for durability and environmental factors across installations to ensure safety under varying conditions.
    The WRAG guidance you introduced (Q1.104) further reinforces this, as it confirms that consumer units complying with BS EN 61439-3 can be installed in detached outbuildings, provided environmental factors are considered. This guidance complements the broader requirements of BS 7671 and supports the use of metallic CUs, particularly those manufactured to Schneider Electric’s high standards, for added durability and fire safety in challenging environments.
    While differing interpretations are a natural part of technical discussions, dismissing valid points as "patently false" or veering off into unrelated areas risks undermining the value of this exchange. For a productive discussion, let’s focus on the specific regulations and standards relevant to ensuring compliance and safety in this context. I’d also like to open this topic up to other colleagues who may have valuable insights to share, as hearing a broader range of perspectives can only enrich the conversation.
    Looking forward to hearing your thoughts on these points.
    Best regards,  

    Gary Jones JIB Technician

  • 0 in reply to Gary Jones

    Hi Gary, it was me who brought up the WRAG question in the discussion. To clarify, the question was asking whether a non-metallic unit could be used in a detached garage.

    -Andrew

  • 0 in reply to Alan B
    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’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’m happy to discuss them.
    Best regards,  
    Gary Jones JIB Technician 

Join us to get the best from IET EngX.

Joining EngX lets you personalise your experience so you stay up to date on the topics that interest you, plus you’ll be able to make connections who are looking to collaborate, exchange ideas and more.

Join us Not now

Community Rules & Guidelines