Plastic consumer unit rental
My rental's CU was changed from metal to plastic in 2012 as I was told metal ones pose a shock risk. The EICR was in 2023 when the plastic CU was marked as a C3.
It's in good condition. However it's high on the wall adjacent to the front door, on what looks like a wooden baseboard. It's not enclosed.
The property is on the ground floor so other means of escape available.
If the CU is in good condition but on a wooden baseboard, must it be changed to a metal one?
Advice from 11 local tradespeople
A plastic consumer unit installed before the current regulations does not automatically need to be replaced simply because it is made of plastic. If your 2023 EICR classified it as C3 (Improvement Recommended), this indicates that it was considered satisfactory for continued use and did not require immediate replacement.
The fact that the consumer unit is mounted on a wooden backboard is also common in older installations and, by itself, does not make the installation unsafe. Since Amendment 3 of BS 7671 (introduced in 2016), new consumer units in domestic premises are generally required to have a non-combustible (typically metal) enclosure to help contain a fire originating within the consumer unit. However, this requirement is not retrospective.
A replacement would normally only be recommended if the consumer unit is damaged, lacks essential protective devices, has signs of overheating, or other observations identified during an EICR indicate it is no longer suitable. If you're unsure, it's worth asking the electrician who carried out the EICR to explain why it was coded C3 and whether any further improvements are recommended.
If the installation remains in good condition and the EICR is satisfactory, there is generally no requirement to replace the plastic consumer unit solely because it is mounted on a wooden backboard.
No, a plastic consumer unit installed before the regulations changed does not automatically need replacing. If it is in good condition and the EICR only recorded it as a C3 (improvement recommended), it is generally considered safe to remain in service.
A metal consumer unit would be an upgrade to current standards, but replacement is not usually mandatory based on the information provided.
Domestic premises: For new installations or alterations in main residential buildings, Regulation 421.1.201 requires consumer units (a type of distribution board) to be made of or enclosed in non-combustible materials, which generally means metal enclosures are mandatory. Plastic ones are not compliant here. However, this rule is not retrospective, so existing plastic boards do not need to be replaced immediately but may be recommended for upgrade during inspections. Additionally, plastic boards are allowed in detached outbuildings like sheds or garages that are not structurally connected to the main house, as fire risk to the main property is low.
No it doesn't have to be changed however it would be marked as a c3 on a condition report, unless however there was signs of thermal damage to the plastic C.U.
It doesn’t need changing just because it’s plastic, especially if it was only given a C3 on the last EICR.
Metal consumer units are preferred these days as they offer better fire protection, but that mainly applies to new installations. If the existing one is in good condition and not causing any issues, it’s generally acceptable to leave it as it is.
The fact it’s on a wooden surface near the front door might make some electricians suggest upgrading for extra safety, but it wouldn’t automatically be a requirement on its own.
In the end, it really comes down to the overall condition of the installation, so it’s best judged in person.
No, you do not automatically need to replace a plastic (PVC) consumer unit just because it’s mounted on a wooden baseboard. There are no regulations that require a plastic CU to be replaced purely due to its mounting surface, provided it is correctly installed, meets current standards, and is not presenting a safety risk. The key factors are enclosure integrity, fire risk, proper enclosing, accessibility, and compatibility with the installation, not the material of the baseboard alone.
The consumer unit does not need to be changed to a metal enclosure solely because it is mounted on a wooden backboard.
The plastic consumer unit was installed in 2012, prior to the introduction of BS 7671:2015 Amendment 3, which introduced the requirement for non-combustible (metal) enclosures. This requirement is not retrospective and applies only to new installations or consumer unit replacements.
The most recent EICR (2023) has recorded the consumer unit as a C3 (Improvement Recommended), confirming that while it does not meet current standards, it is not unsafe and is satisfactory for continued use. If the installation were considered unsafe or posed a significant fire risk, it would have been coded C2 or FI.
Although the consumer unit is mounted on a wooden backboard and located near the front door, there is no regulation requiring an existing plastic consumer unit in good condition to be replaced on this basis alone. The property is on the ground floor and has alternative means of escape, further reducing any concern regarding means of egress.
In summary, there is no regulatory requirement to replace the existing plastic consumer unit with a metal one unless it is being replaced as part of new works, shows signs of deterioration, or is otherwise deemed unsafe.
You will have an issue having it mounted on a flammable surface regardless of whether it's metal or plastic. I would look to have it changed to a metal CU, verify if the mounting board is flammable or not (there are mounting boards that look like wooden board but are flame retardant), and also look at getting the board and associated distribution equipment (meter, main fuse etc) enclosed for fire compartmentation. Some of the regs regarding this are outside BS7671 so not every electrician will be able to give you a 100% answer.
You don’t have to change your plastic consumer unit (CU) to a metal one right now.
• Plastic CUs installed before 2016 (like yours, fitted in 2012) are ok to keep if they’re in good condition have necessary RCD protection Type A preferably.
Mounting it on wood isn’t banned, as long as the wood is dry and safe.
The C3 mark means 'improvement recommended' (not 'dangerous') – it just falls short of current standards, not that it’s illegal. Improvement is recommended to keep up to
Date with today’s current regulations such as Metal distribution board with RCBO.
You can keep using it for now, but your electrician can advise on small tweaks to fix the C3 rating if you want
A plastic consumer unit is still acceptable as long as it’s in good condition and not showing any signs of heat damage. Metal consumer units only became mandatory for new installs from January 2016 under Amendment 3 of BS 7671, mainly to reduce fire spread in escape routes.
Because your board was installed before that date and has been coded as a C3 (recommendation only) on the EICR, it does not have to be replaced. A C3 means it’s safe for continued use.
Having it on a wooden backboard also isn’t a fail by itself. Older properties commonly have this, and it’s fine as long as:
• The CU is secure,
• There’s no overheating,
• The main tails and terminations are sound,
• No signs of scorching or thermal damage.
Since the property has alternative escape routes and the board isn’t showing heat issues, there’s no requirement to upgrade it to a metal consumer unit. It’s simply something that may be recommended for modernisation, not a legal or safety obligation.
No, it Doesn't have to be changed; aslong S the fixings are secure. The EICR will have a C3 against the board (thats because the new regulations state SPD and Metal board (for Fire ricks, to try contain the fire) as obviously plastic ones would melt. C3 isnt a fail, it a recommendation for improvement.
