The distance between the distribution box and the switch box should not exceed 30 meters, and the horizontal distance between the switch box and the fixed electrical equipment it controls should not exceed 3 meters. This proximity principle reduces line losses and improves. For three-phase four-wire systems used in distribution boxes, the standard wire colors must be followed: Phase A - Yellow, Phase B - Green, Phase C - Red, Neutral wire - Light Blue, Protective Earth wire - Yellow/Green bi-color. The use of Yellow/Green bi-color wire for any other purpose is. Within the same building, the installation height of the same type stainless steel printer enclosure should be consistent, with an allowable deviation within 10 millimeters. This uniformity is not only aesthetically pleasing but also facilitates later systematic management. Choosing a suitable. Specification synopsis: This specification provides standard tolerances for concrete construction. Commentary synopsis:. 2)The distribution box shall be installed firmly, horizontal and vertical, and the vertical deviation shall not be greater than 3mm; During concealed installation, there shall be no gap around the distribution box, the edges around the panel shall be close to the wall, and the contact part between. This document has primarily been drafted to enable builders, contractors and home owners to reference general building standards related to domestic construction and hopefully to minimise the likelihood of disputes in relation to the quality of building work occurring.