Consumer unit EICR observations explained

Helpful video reference. We use Matt O'Dell's video "EICR Consumer Unit Issues -- Eddy Currents, IP Ratings and Torque Setting of MCB's" as the video reference here. Matt is a qualified UK electrician whose channel covers technical content in plain English. This video is one of the most useful explanations of these three observations and what they mean in practice.

1. Understand the EICR code system

Every item on an EICR report is assigned one of four codes:

• C1 -- Danger present. A risk of electric shock or fire exists right now. The installation should not remain in use without immediate remedial work.
• C2 -- Potentially dangerous. A defect that could become dangerous. Remedial work is required before a satisfactory certificate can be issued.
• C3 -- Improvement recommended. Not dangerous, but not fully compliant with current standards. The certificate can still be satisfactory, but you should plan to address the item.
• FI -- Further investigation required. The inspector could not fully assess the item. Additional testing is needed before a final code is assigned.

Consumer unit observations are commonly C2 or C3. A C1 at the consumer unit -- live parts exposed and accessible, for example -- would result in a failed certificate and a recommendation not to use the installation until the work is done.

2. IP rating: can the live parts be touched?

IP stands for Ingress Protection. The relevant requirement for consumer units is IP2X -- a 12 mm round probe (roughly the diameter of a child's finger) must not be able to contact any live part inside the enclosure.

In practice, an inspector checks for missing busbar blanks (the plastic covers that fill unused MCB slots on the busbar), open cable gland knockouts, and whether the enclosure lid closes fully and fastens correctly. Any of these can mean a live part is accessible and the IP2X requirement is not met.

Missing busbar blanks are the most common finding. They are inexpensive and quick to fit -- usually a C2 observation that is straightforward to resolve. Open knockouts where cables pass through without a grommet or blanking plate are also common, particularly on older boards.

3. Eddy currents from single-core cable routing

Most modern consumer units connect to the incoming supply via single-core cables -- a separate brown (live) and grey or blue (neutral) conductor, plus a green-yellow earth. If these cables are routed individually through separate steel knockouts or steel glands in the enclosure, the alternating current in each conductor creates a changing magnetic field that induces circulating currents in the surrounding steel.

These eddy currents waste energy as heat, cause localised heating of the enclosure material, and can over years degrade cable insulation near the entry points. The fix is straightforward: all conductors of the same circuit (live, neutral, earth) should pass through the same gland or knockout together. Non-ferrous gland materials such as nylon or brass also prevent eddy current formation entirely.

On an EICR this is typically a C3. It is not immediately dangerous, but it should be corrected at the next opportunity -- often when other consumer unit work is being done anyway.

4. MCB torque settings

Every terminal on a consumer unit -- the incoming supply terminals, busbar connections, and individual MCB conductor terminals -- has a manufacturer-specified torque value. For most MCB conductor terminals this is between 1 Nm and 3 Nm, though it varies by device size and manufacturer.

Under-torqued conductors can work loose over time. A loose terminal creates resistance, which creates heat, which can cause insulation damage, arcing, and in the worst case a fire. Over-torqued terminals can crack the conductor insulation or strip the terminal thread.

An inspector checks torque with a calibrated torque screwdriver and re-torques any conductor that is out of specification. This is particularly common on older consumer units that have not had maintenance and on installations where untrained work has been done near the board. Incorrect torque is typically a C2 when significantly under-torqued, or C3 when only slightly out of specification.

5. Missing or incorrectly rated protective devices

The MCB or fuse protecting a circuit must match the cable cross-section and the expected load. A 32 A MCB on a 1.5 mm cable is oversized -- the MCB will not trip before the cable overheats. This is a C2 and needs prompt correction.

Since the 17th Edition of BS 7671, most socket outlet circuits must also have additional protection from a 30 mA RCD. Older installations without RCD protection on socket circuits will receive a C3 in most domestic settings, or C2 for higher-risk locations such as a garage or outdoor sockets. An inspector will note which circuits lack this protection.

6. Consumer unit age and enclosure condition

Consumer units manufactured before BS EN 61439-3 became the relevant product standard may use plastic enclosures that are not classified as non-combustible. A fire starting inside an older plastic consumer unit can spread more readily than one in a modern steel or thermoplastic enclosure.

This is typically a C3, not an immediate C2, unless the enclosure is visibly damaged. An older plastic consumer unit that is otherwise in good condition may not need immediate replacement, but the observation is a legitimate basis for planning a replacement over the next few years.

When to call us

If you have received an EICR with consumer unit observations and want a second opinion on the codes, or if you need the remedial work carried out, Richard does EICR inspections and consumer unit remedial work across east Kent. Call or email to discuss what your report says and what the options are.