A cable for a lamp string is provided herein. The cable may include a number of wires arranged in parallel and aligned in a planar manner, or in a V- or W-like manner. One or more of the wires may be flexible wires or tensile wires. The flexible wire has a core made of a bendy material capable of retaining a new shape, and the tensile wire has a core made of a nonconductive and tensile material.

A LED luminaire for use in a livestock barn includes a base plate provided with at least one first LED arrangement configured to, in operation, emit light which simulates daylight lighting conditions. The first LED arrangement includes a plurality of LEDs of a first type, which has at least one peak wavelength in the wavelength range between 500 and 600 nm, and at least one LED of a second type, which is a blue LED with its peak wavelength in the wavelength range between 440 and 480 nm. The luminaire is provided with an optical system configured so that the intensity of light emitted by the LEDs is distributed according a distribution which has its peak intensity at an angle of more than zero degrees from the optical axis of the luminaire.

A portable power supply system for providing portable electrical power includes a battery that has a positive terminal and a negative terminal. A box is provided and the battery is positioned in the box. A lid is removably coupled to the box. A pair of first light emitters is provided and each of the first light emitters is removably coupled to the lid to selectively emit light outwardly from the lid. An inverter is removably coupled to the lid and the inverter may be electrically coupled to an electric device thereby facilitating the inverter to supply AC current to the electric device.