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Electrical Glossary & Other Information (Read 123877 times)

LSpark

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Electrical Glossary & Other Information
Sep 29^th, 2004, 2:59pm

Electrical Glossary & Usefull Information

Here's a few Electrical Terms that we have listed in alphabetical order to help alleviate any confusion

CCT - Circuit
CCU - Cooker Control Unit
CPC - Circuit Protective Conductor
CU - Consumer Unit
EEBAD - Earthed Equipotential Bonding And Automatic Disconnection Of Supply
ELV - Extra Low Voltage = Below 50V AC \ 120V Ripple Free DC
FCU - Fused Connection Unit
FELV - Functional Extra Low Voltage
HBC - High Breaking Capacity
HRC - High Rupturing Capacity
HV - High Voltage
LV - Low Voltage = 50V - 1000V AC \ 1500V Ripple Free DC
MCB - Miniature Circuit Breaker
MCCB - Moulded Case Circuit Breaker
MD - Maximum Demand
MICC - Mineral Insulated Copper Cable aka Pyro
PAT - Portable Appliance Testing
PELV - Protected Extra Low Voltage
PEN - Protective Earthed Neutral
PFC - Prospective Fault Current
PME - Protective Multiple Earthing
PSCC - Prospective Short Circuit Current
PVC - Poly Vinyl Chloride
RCBO - Residual Current Breaker With Integral Overload Protection
RCCB - Residual Current Circuit Breaker
RCD - Residual Current Device
SELV - Separated Extra Low Voltage
SRCBO's - Socket Outlet Incorporating RCBO's
SWA - Steel Wire Armour (Cable)
UPS - Uninterruptible Power Supply
VD - Voltage Drop

A - Amp
W - Watt
V - Volt
R - Resistance
Z - Impedance
mA - milliampere
mV - millivolt
kW - Kilowatt
kV - Kilovolt

Feel free to PM me with any additional ones you think are appropriate and should be added.
Cable Identification Charts

Thanks for Looking!

Created 29/9/04 - Updated 19/4/05

« Last Edit: Apr 7^th, 2006, 12:21am by LSpark »

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Lectrician

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Re: Electrical Glossary & Other Information
Reply #1 - Apr 11^th, 2005, 9:47am

Two Way Switching

Two way switching is most commonly found on stairs and landings, and long corridors. There are a few different methods of providing a 2-way switching circuit, these are shown below.

Please note that the below diagrams have been drawn with the older cable core colours. Although these are predominantly still found in installations, the newer colours are beginning to come into circulation.

As a rule for these diagrams, RED becomes BROWN ; YELLOW becomes BLACK ; BLUE becomes GREY ; BLACK becomes BLUE.

You may find that the cables between the switches in your property have been connected with a different colour coding. This makes no difference to operation, as long as the colour at one switch matches that of the other(s).

Standard Method

Cable Saving Method

This method requires an extra terminal block to be placed inside the ceiling rose, light fitting or joint box.

Conduit Method

This method is most suited to conduit work, where the cables are single cores installed inside conduit or trunking. It can also be utilised, with adaption, in a domestic environment using standard Twin & Earth cable or double insulated single cores.

This method is most suited to conduit work, where the cables are single cores installed inside conduit or trunking. It can also be utilised, with adaption, in a domestic environment using standard Twin & Earth cable or double insulated single cores.

If more than two switching positions are required, an INTERMEDIATE switch (or more) will be required. These are placed in the cables between the two 2-way switches (known as the strappers), and 'break' into the L1 and L2 conductors. The Common (usually yellow) conductor is kept continuous, a terminal block is required for this.

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Lectrician

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Re: Electrical Glossary & Other Information
Reply #2 - Apr 11^th, 2005, 9:47am

Earthing Arrangements

There are 3 main commonly used Earthing Arrangements found in domestic installations.

TN-C-S ; TN-S ; TT

The T stands for 'TERRA' which is 'earth' in Latin.
The C stands for 'COMBINED' in relation to the neutral and the earth.
The S stands for 'SEPERATE' in relation to the neutral and the earth.

TN-C-S

A TN-C-S system has the neutral and earth COMBINED in the Electricity Boards supply cable(s), and SEPERATE with in the installation, (this being the meter position and onwards).

TN-S

A TN-S system has the neutral and earth SEPERATE through-out the entire system, including the Electricity Boards Supply cable(s).

OR

OR

TT

A TT system has the neutral running in the supply cable(s) as normal, and the earth from the installation is connected to an appropriate Earth Electrode inserted into the ground. An RCD is essential in an installation formed by a TT earthing arrangement.

It is the Electricity Boards responsibility to provide a TN-C-S or a TN-S supply, if requested and available, it is not their responsibility to provide a TT earthing arrangement.

In order for the Electricity Board to provide a TN-C-S supply, they have to construct their network to the standards of PME (protective multiple earthing), this is why a TN-C-S system is often referred to as a PME installation.

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Lectrician Administrator Trade Member Author Offline Ask The Trades Posts: 8815 Total Thanks: 109 For This Post: 0 Braunton, North Devon United Kingdom Gender: Trade: Electrician	Re: Electrical Glossary & Other Information Reply #3 - May 16^th, 2005, 5:59pm Maximum Values Of Earth Fault Loop Impedance Corrected To 80% 'Rule Of Thumb' 16th Edition!
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Lectrician Administrator Trade Member Author Offline Ask The Trades Posts: 8815 Total Thanks: 109 For This Post: 0 Braunton, North Devon United Kingdom Gender: Trade: Electrician	Re: Electrical Glossary & Other Information Reply #4 - May 21^st, 2005, 5:50pm Courtesy of BATTS Cables - Reproduced by Lectrician. Sorry for the poor quality - when converting to a gif file, the spreadsheet hidden lines have re-appeared! NOTE - These figures are given as ohms per kilometer. This is exactly the same as milli-ohm per meter (you still have 3 zero's in the fraction )
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supersparky

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Re: Electrical Glossary & Other Information
Reply #5 - Jun 17^th, 2005, 10:15pm

IP CODES

First numeral: mechanical protection
0 No protection of persons against contact with live or moving parts inside the enclosure.
No protection of equipment against ingress of solid foreign bodies.

1 Protection against accidental or inadvertent contact with live or moving parts inside the enclosure by a large surface of the human body, e.g. a hand, but not protection against deliberate access to such parts. Protection against ingress of large solid foreign bodies.

2 Protection against contact with live or moving parts inside the enclosure by fingers.
Protection against ingress of medium size foreign bodies.

3 Protection against contact with live or moving parts inside enclosure by tools, wires or such objects of thickness greater than 2.5mm.
Protection against ingress of small solid foreign bodies.

4 Protection against contact with live or moving parts inside the enclosure by tools, wires or such objects of thickness greater than 1mm.
Protection against ingress of small solid foreign bodies.

5 Complete protection against contact with live or moving parts inside the enclosure.
Protection against harmful deposits or dust. The ingress of dust is not totally prevented, but dust cannot enter in an amount sufficient to interfere with satisfactory operation of the equipment enclosed. (Dustproof)

6 Complete protection against contact with live or moving parts inside the enclosure.
Protection against ingress of dust. (Dust tight)

Second numeral: liquid protection

0 No protection

1 Protection against drops of condensed water
Drops of condensed water falling on the enclosure shall have no harmful effect. (Drip proof)

2 Protection against drops of liquid. Drops of falling liquid shall have no harmful effect when the enclosure is tilted at any angle up to 15° from the vertical.

3 Protection against rain. Water falling in rain at an angle equal to or smaller than 60° with respect to the vertical shall have no harmful effect. (Rain proof)

4 Protection against splashing. Liquid splashed from any direction shall have no harmful effect. (Splash proof)

5 Protection against water jets. Water projected by a nozzle from any direction under stated conditions shall have no harmful effect. (Jet proof)

6 Protection against conditions on ships decks (deck watertight equipment). Water from heavy seas shall not enter the enclosure under prescribed conditions.

7 Protection against immersion in water. It shall not be possible for water to enter the enclosure under stated conditions of pressure and time. (Immersible)

8 Protection against indefinite immersion in water under specified pressure. It shall not be possible for water to enter the enclosure. (Submersible)

an X indicates no specified protection

« Last Edit: Oct 1^st, 2005, 2:09pm by Lectrician »

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Lectrician

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Re: Electrical Glossary & Other Information
Reply #6 - Jan 19^th, 2006, 7:14am

There are two main types of single phase concentric cables available. STRAIGHT CONCENTRIC and SPLIT CONCENTRIC.

STRAIGHT CONCENTRIC will not comply with BS7671! This is because the neutral is single insulated and not identified. This type of cable is used primarily in the distribution of electricity by the electricity supply companies.

SPLIT CONCENTRIC cable will comply to BS7671. This type of cable can be treated like standard Twin & Earth type cables. It also offers penetration protection (A nail WILL penetrate, but will always short live to earth or neutral). It WAS often refered to in the 16th edition of BS7671 for use outside safe wiring zones. This is not the case with the 17th edition.

SPLIT CONCENTRIC cable can be terminated at consumer units, distribution boards, switch fuses and other accessories as if it was a standard PVC Twin and Earth cable. No glands are required.

Here is a photo of 16mm² Split Concentric with only the sheath removed. The single green and white strands are purely nylon packers - they are not conductors.

Here is a photo of 16mm² Split Concentric ready to be used (gently twisted neutrals, sleeved earth) - you could use one peice of large earth sleeve, but this makes the earthing conductors difficult to form.

Here is a photo from my camera phone (excuse quality). This is 25mm² Split Concentric terminated into a metal clad Consumer Unit, using a standard brass bush and locknut. The cable is cleated/clipped to the wall to give strain relief.

Here is a photo of some fairly rare 3 core 16mm² Split Concentric stripped and prepared. Typically used by the DNO for TN-S supplies.

Here is a photo of 16mm² Straight Concentric with the sheath removed.

Here is a photo of 16mm² Straight Consentric ready to be used. The CNE conductor (combined neutral and earth) is gently twisted together - no tools used. It is best not to tighted with tools, as this can damage the crutch of the cable, and lead to a hotspot if the cable is run warm.

REMEMBER

STRAIGHT CONCENTRIC cannot be used if you are wanting to comply to BS7671! You may use SPLIT CONCENTRIC within BS7671, and this can be treated like standard Twin & Earth type cables. It also offers penetration protection (A nail WILL penetrate, but will always short live to earth or neutral). It WAS often refered to in the 16th edition of BS7671 for use outside safe wiring zones. This is not the case in the 17th edition.

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Lectrician Administrator Trade Member Author Offline Ask The Trades Posts: 8815 Total Thanks: 109 For This Post: 0 Braunton, North Devon United Kingdom Gender: Trade: Electrician	Re: Electrical Glossary & Other Information Reply #7 - Mar 21^st, 2010, 6:46pm Use Of SWA Armouring As A Protective Conductor This is a replication of the article in the NIC Connections Magazine, issue 152.
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Lectrician Administrator Trade Member Author Offline Ask The Trades Posts: 8815 Total Thanks: 109 For This Post: 0 Braunton, North Devon United Kingdom Gender: Trade: Electrician	Re: Electrical Glossary & Other Information Reply #8 - Apr 28^th, 2010, 6:51pm Fork Truck Battery Chargers Chloride Motive Power (under other names too).
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Lectrician Administrator Trade Member Author Offline Ask The Trades Posts: 8815 Total Thanks: 109 For This Post: 0 Braunton, North Devon United Kingdom Gender: Trade: Electrician	Re: Electrical Glossary & Other Information Reply #9 - Jun 13^th, 2012, 9:30pm High definition PDF file: CLICK HERE
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