No terms match that. Try a shorter word, or ask us directly.
A
- AFDD (arc fault detection device)
- A device that switches off a circuit when it detects arcing from a loose connection or damaged cable. Required in some buildings, such as HMOs and high-rise flats, and recommended elsewhere. RCD or RCBO: which should you have?
B
- BS 7671
- The UK wiring regulations, published by the IET. The current version is the 18th Edition. It applies to new electrical work, not retrospectively to existing installations. Is a plastic consumer unit illegal?
C
- C1, C2, C3 and FI
- The codes on an EICR. C1 is danger present, C2 is potentially dangerous, FI is further investigation required, and C3 is improvement recommended. Any C1, C2 or FI makes the report unsatisfactory. EICR codes C1, C2, C3 and FI explained
- Circuit
- One run of cable from the board feeding a group of sockets, lights or a single appliance such as a shower or oven. Each circuit has its own protective device on the board.
- Competent person scheme
- A government-approved scheme, such as NAPIT, whose registered electricians can self-certify notifiable work under Part P and notify Building Control for the homeowner. Part P and fuse box replacement
- Consumer unit
- The technical name for a fuse box or fuse board: the box that splits the incoming supply into circuits and protects each one. Since 2016, new ones in homes must be non-combustible, which in practice means metal. Fuse box or consumer unit: any difference?
- Cut-out
- The sealed box where the supply enters the house, containing the main fuse. It belongs to the network operator, Electricity North West in Greater Manchester, and must not be opened by anyone else. Fuse box or consumer unit: any difference?
D
- Dual-RCD (split-load) board
- A consumer unit with circuits divided into two groups, each behind one RCD. Common from about 2008 to 2015. One fault switches off every circuit in the group. RCD or RCBO: which should you have?
E
- EIC (Electrical Installation Certificate)
- The certificate an electrician issues for new work such as a consumer unit replacement, recording what was installed and the test results for every circuit. Part P and fuse box replacement
- EICR (Electrical Installation Condition Report)
- An inspection and test of an existing installation, with each finding coded. Landlords in England need a satisfactory one at least every five years. EICR codes C1, C2, C3 and FI explained
- Earthing
- The connection that gives fault current a safe path to earth so protective devices can operate. Older properties sometimes need an earthing upgrade, which we price at £80 to £160.
F
- Fuse box
- The everyday name for a consumer unit, from the days when every circuit had a fuse. Also called a fuse board. Fuse box or consumer unit: any difference?
M
- Main protective bonding
- Green and yellow cables connecting incoming gas and water pipes to the main earthing terminal. Missing or undersized bonding is a common C2 on an EICR. We price it at £80 to £150. EICR codes C1, C2, C3 and FI explained
- Main switch
- The switch on the consumer unit that turns off every circuit at once. It does not isolate the meter tails or the cut-out. How to reset a tripped fuse box
- MCB (miniature circuit breaker)
- A switch that protects a circuit from overload and short circuit. It replaced the fuse, but on its own gives no protection against electric shock. RCD or RCBO: which should you have?
- Meter tails
- The two thick cables between the electricity meter and the consumer unit. Normally the homeowner's responsibility. New tails cost £60 to £120 when fitted with a new board. Fuse box or consumer unit: any difference?
N
- Notifiable work
- Electrical work that Building Control must be told about under Part P, including replacing a consumer unit and adding a new circuit. Part P and fuse box replacement
P
- Part P
- The part of the Building Regulations in England covering electrical safety in homes. A consumer unit replacement is notifiable under Part P. Part P and fuse box replacement
R
- RCBO
- A combined RCD and MCB protecting a single circuit. A fault switches off only that circuit. Every board we fit has an RCBO on every circuit. RCD or RCBO: which should you have?
- RCD (residual current device)
- A device that switches off the power in a fraction of a second when it detects current leaking to earth, such as through a person touching something live. Rated at 30mA for most household circuits. RCD or RCBO: which should you have?
- Rewireable fuse
- An old-style fuse carrier holding a length of fuse wire that melts when overloaded. Boxes with rewireable fuses have no RCD protection. How to reset a tripped fuse box
S
- SPD (surge protection device)
- A module on the consumer unit that diverts short voltage spikes to earth, protecting electronics. Expected on most new domestic boards since the 18th Edition. Do you need surge protection?
T
- Type A RCD
- An RCD or RCBO that detects both alternating and pulsating DC leakage, which modern appliances and LED drivers can produce. The normal choice for household circuits. RCD or RCBO: which should you have?
W
- Way
- One slot in a consumer unit for a protective device. A ten-way board has room for ten. A spare way is needed to add a circuit for a shower or EV charger. Can my board take a shower or EV charger?
