A short-term exposure limit (STEL) is the acceptable average exposure over a short period of time, usually 15 minutes as long as the time-weighted average is not exceeded.

Usually due to a fault, current is allowed to flow along an unintended path.

In physics, the Shockley–Queisser limit is the maximum theoretical efficiency of a solar cell using a single p-n junction to collect power from the cell where the only loss mechanism is radiative recombination in the solar cell.

A shielded cable or screened cable is an electrical cable of one or more insulated conductors enclosed by a common conductive layer.

Shell and tube heat exchangers consist of a series of tubes which contain fluid that must be either heated or cooled.

Shear stress is the component of stress coplanar with a material cross section.

In solid mechanics, shearing forces are unaligned forces pushing one part of a body in one specific direction, and another part of the body in the opposite direction.

Water depths less than 30 meters. Considered when offshore wind farms are being planned.

A shaft is a rotating machine element, usually circular in cross section, which is used to transmit power from one part to another, or from a machine which produces power to a machine which absorbs power.

The wind-turbine shaft is connected to the center of the rotor.

A shading coil or shading ring is a single (or a few) turn of electrical conductor (usually copper or aluminum) located in the face of the magnet assembly or armature of an alternating current solenoid.

In control engineering a servomechanism, sometimes shortened to servo, is an automatic device that uses error-sensing negative feedback to correct the action of a mechanism.

A company, team or individual that provides information, resources to meet a clients requirements.

A measure of how a machine or other equipment can easily be serviced.

Service reservoirs store fully treated potable water close to the point of distribution.

Original designer of the helical turbine whereby the blades are configured in a vertical helix.

A two-stroke (or two-cycle) engine is a type of internal combustion engine that completes a power cycle with two strokes (up and down movements) of the piston during only one crankshaft revolution.

Two-photon photovoltaic effect (TPP effect) is an energy collection method based on two-photon absorption (TPA).

A two-tariff electricity meter which records separately the electricity used during the off-peak period so that it can be billed at a lower rate.

An alternating current electricity power that utilises two circuits with offset phases. Two phase electricity generation has been generally replaced by 3 phase electricity generation.