Someone asked about abbreviations used here. So I tried to copy a list I made elsewhere:
A/C | Air Conditioning |
AC | Alternating Current |
ACB | Air Circuit Breaker (typically larger than a MCCB) |
ATS | Automatic Transfer Switch (typically for mains to backup supply such as a generator) |
BC | Bayonet Cap (type of light socket, was UK standard) |
BS | British Standard. Official standards for goods and services in the UK as issued by the BSI (often based on other body’s work, such as the IET for wiring, etc) |
BS88 | British standard covering fuses |
BSI | British Standards Institution |
BZP | Bright Zinc Plating |
CCC | Current-Carrying Capacity |
CCTV | Closed-circuit Television (generic term now for video monitoring) |
CPC | Circuit Protective Conductor (informally referred to as the “Earth wire” even though it is not usually directly connected to the Earth point). |
CU | Consumer Unit (distribution board for domestic electrics) |
DB | Distribution Board |
DC | Direct Current |
DIN | Deutsches Institut für Normung (German standards body, like the BSI in the UK) often used as a shorthand way to reference engineering products originating in Germany such as the mounting rail system used for most MCBs, etc. |
DP | Dual Pole (2-pole) |
ELV | Extra Low Voltage (typically below 50V AC) |
EM | Electro-Magnetic |
EMC | Electro-Magnetic Compatibility (ability of equipment to operate in, and not unduly pollute, a given radio environment) |
ES | Edison Screw (type of light socket, was USA standard) |
EU | European Union |
FCU | Fused Connection Unit |
GDT | Gas Discharge Tube (type of SDP) |
HRC | High Rupture Capacity (of a fuse, typically using a sand-filled ceramic body) |
LRC | Low Rupture Capacity (typically glass) |
HV | High Voltage (generally above 1kV, but sometimes MV is used for 1-35kV range with HV used for 35-230kV) |
IEC | International Electrotechnical Commission (often used as short hand for connectors based on those standards, e.g. the “kettle lead” in the UK) |
IEE | Institution of Electrical Engineers, they became the IET in 2006. |
IEEE | Institute of Electrical and Electronics Engineers, the USA professional body for electrical/electronic engineers. |
IET | Institution of Engineering and Technology Formed in 2006 from two separate institutions: the Institution of Electrical Engineers (IEE) and the Institution of Incorporated Engineers. |
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IR | Infrared (of light), Insulation Resistance (of electrical testing) |
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IT | Information Technology (computers and related equipment), Isolé-Terre (of power supply, from the French for isolated from Earth) where there is no low-impedance connection to the Earth. Typically used only in medical systems or ships where it is important to survive a single-fault condition and where competent (electrically speaking) monitoring is always present. |
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LED | Light Emitting Diode |
LV | Low Voltage (in power supply terminology this is below 1000V AC / 1500V DC) |
MCB | Miniature Circuit Breaker |
MCCB | Moulded Case Circuit Breaker (larger and higher current capability than MCBs) |
MES | Medium Edison Screw (type of lamp base) |
MOV | Metal Oxide Varistor (type of SPD) |
MV | Medium Voltage (typically 1-35kV) |
NFPA | National Fire Protection Association, original authors of the USA’s wiring standards |
OCPD | Over Current Protective Device (typically a fuse or MCB/MCCB used to limit the duration of any fault current). |
PC | Personal Computer (generic term, and medium sized computer but generally based on the x86 processor family) |
PCB | Printed Circuit Board, Polychlorinated Biphenyl (highly toxic oil formally in capacitors, transformers, etc, now banned) |
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PFC | Prospective Fault Current (typically from phase to earth) |
PIR | Passive Infrared (movement detector based on heat) |
PME | Protective Multiple Earthing (the combined E & N in TN-C-S systems) |
PPE | Personnel Protective Equipment |
PSCC | Prospective Short-Circuit Current |
PTC | Positive Thermal Coefficient, a device who’s resistance increases with temperature (in particular from self-heating) |
PVC | Polyvinyl Chloride (common type of insulation) |
RCBO | Residual Current Breaker with Overload protection (MCB & RCD combined) |
RCD | Residual Current Device |
RCCB | Residual Current Circuit Breaker |
SP | Single Pole |
SPD | Surge Protection Device |
SWA | Steel Wire Armour |
TN-C | A combined protective earth & neutral conductor fulfils the functions of both a PE and an N conductor. Used for some power distribution but not permitted for final installations in the UK due to the safety risk of an open PEN fault. |
TN-C-S | A combined protective earth & neutral conductor fulfils the functions of both a PE and an N conductor up to the supply point of an installation (so TN-C here), at which point they are separated (so TN-S within the installation). Commonly used in the UK where this system is also known as protective multiple earthing (PME). Similar systems in Australia and New Zealand are designated as multiple earthed neutral (MEN) and in North America as multi‑grounded neutral (MGN). |
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TN-S | The protective earth and neutral are separate conductors that are connected together only near the power source, where that connect to the Earth |
TPN | Three Phase and Neutral |
TT | Terre-Terre, power supply arrangement where the local Earth (terre in French) is used for protective grounding both at the source and at the end user. |
UPS | Uninterruptable Power Supply |
UV | Ultra Violet |
XLPE | Cross-linked polyethylene |
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