What is considered medium voltage, and how well do you know medium voltage power terminology?
If you have ever been on a job site or tried to order parts, you probably know that contractors and electricians have some—creative—names for things, and medium voltage connections are no different Slang terms can mean different things to different people, and it is especially important to make sure you know what product you are talking about when you are ordering medium voltage materials. If not, things can blow up—literally!
To help you differentiate between your medium voltage connections, terminations, joints and more, watch Misty Williams, 3M’s Midwest Regional Distribution Leader, explain the meanings of some common medium voltage slang terms, or check out the medium voltage slang term dictionary below.
WHAT IS CONSIDERED MEDIUM VOLTAGE?
Medium voltage is higher than 600V and lower than 35kV. For reference, THHN wire is 600V rated, and most switchgear and medium voltage transformer ratings stop around 35kV. It is mainly used in heavy industrial settings and in large campuses where power needs to be spread out over a considerable distance.
Here are some terms you might come across as you order and work with medium voltage connections, splices, elbows and more:
MEDIUM VOLTAGE SLANG DICTIONARY
Medium Voltage Splicing Terminology
- Aerial—Overhead cable and accessories; mounted or suspended in air (e.g. triplex)
- Branch—A branch splice is a Y or tap splice (a 3-way splice)
- Butt—Another name for an inline splice
- Cold Shrink—Joint made of tubes(s) that are applied by shrinking without heat
- Extruded—Joint in which cables are insulated with extruded dielectrics
- Filled—Joint with outer shell that is filled with insulating compound (potted)
- Grounding Tab—Tab molded into semi-con jacket for ground wire attachment
- Joint—Official name for a splice
- Oil Stop—Sealing a PILC accessory to confine oil to the PILC cable
- Premolded—Joint that is factory molded in the shape it will take when installed
- Transition—Joint of two cable types; e.g. EPR to PILC; 3/C to 3-1/C; etc.
- Trifurcating—three branches; transition from 3/C to 3-1/C cables
- Wye—“Y” splice configuration or splice where tap meets a run at a diagonal
Medium Voltage Terminating Terminology
- Breakout—Crotch where three conductors exit a three-conductor cable jacket
- Class 1—IEEE 48 termination class: 1-stress control, 2-insulator and 3-seal
- Class 2—IEEE 48 termination class: 1-stress control, 2-insulator and 3-seal
- Creepage—Distance between conductor and ground along insulator contour
- High K—Method of stress control based on high-dielectric constant materials
- Hippy—High-potential, low energy, cable field test; usually direct current
- Inverted—Installation where shielded cable is fed from above (upside-down)
- Live Front—Connection that is not fully insulated and shielded
- Pothead—1/C or 3/C porcelain termination or any termination
- Skirted—Insulator with skirts to increase creepage and break up moisture path
- Stinger—Slang for “stem connector”
- Stress Cone—Method of stress control; also used to mean termination
- Termination—Device for terminating AC-shielded power cables
- Terminator—Another word meaning termination
Medium Voltage Elbows Terminology
- 200 Amp—Designated 200-amp current which elbow can carry continuously
- 600 Amp—Designated 600-amp current which elbow can carry continuously
- Cable Adapter—Premolded insert T adapt elbow to specific cable diameter
- Connecting Plug—600-amp elbow accessory for connecting T modules together
- Connecting Stud—Threaded stud used with 600-amp connecting plug and dead ends
- Dead-Break—Separating an elbow from a de-energized circuit
- Dead-Front—No exposed live parts; exposed parts insulated, shielded and grounded
- Hammerhead—Slang for 600-amp “T” module
- Load-Break—Designed to close and interrupt current on energized bushing
- Load-Make—Installing a load-break elbow onto an energized bushing
- Modular—600-amp elbow system which can be used in many configurations
- Probe—Arc-extinguishing rod connected to elbow compression connector
- Shotgun Stick—Insulated operating stick for installing elbows and components
- Test Point—Capacitively coupled terminal for use with voltage-sensing devices
- Two-Way—Elbows used as a splice for connecting two cables
Medium Voltage Motor Leads Terminology
- Peckerhead—Another term for a motor lead boot assembly
