RISER - A UL designation for cable approved to go from one floor to another floor in a multistory building.
RMS - Abbreviation for Root Mean Square. It is a means of expressing AC voltage in terms of DC. It is approximately 80% of AC peak voltage.
ROENTGEN - The amount of radiation that will produce one electrostatic unit of ions per cubic centimeter volume.
RoHS - RoHS is the acronym for Restriction of Hazardous Substances. RoHS, also known as Directive 2002/95/EC, originated in the European Union and restricts the use of specific hazardous materials found in electrical and electronic products. All applicable products in the EU market after July 1, 2006 must pass RoHS compliance. For the complete directive, see Directive 2002/95/EC of the European Parliament. The substances banned under RoHS are lead (Pb), mercury (Hg), cadmium (Cd), hexavalent chromium (CrVI), polybrominated biphenyls (PBB) and polybrominated diphenyl ethers (PBDE).
ROPE LAY STRAND - A conductor made of multiple groups of filaments. A 7 x 19 rope lay strand has 19 wires laid into a group and then 7 such groups laid cabled into a conductor.
RR - An all rubber nonmetallic underground cable suitable for direct burial in the earth or in conduit. It has heat and moisture resistant insulation and an outer Neoprene® jacket. Neoprene® is a trademark of the DuPont de Nemours Co.
RUB - Abbreviation for rubber.
RUBBER MOLD - A metal mold containing a cavity that will give the desired form or part. The part is made by placing uncured rubber or synthetic compound in the cavity and curing under heat and pressure.
S - a) Abbreviation for silver-plated copper. Also abbreviated as SPC. b) 600 volt senior service rubber insulated portable cord. 18 AWG two conductor through 6 AWG four conductor.
S BAND - A band of microwave frequencies. See frequency band.
SA - a) Abbreviation for silver-covered alloy. b) Nomenclature for silicone rubber insulation with high temperature barrier or glass overall for use up to 125° C.
SC - Abbreviation for silver-covered copper. Also abbreviated as SCC.
