Grounding issue of the on-site instrument panel

What kind of instrument panel? We have one here that isn’t made of metal

Polyurethane box enclosures do not need to be grounded, while flame-retardant metal boxes require protective grounding; there should be a grounding point on the enclosure

Typical protection boxes are grounded through the mounting brackets during installation, so there is no need to connect an additional grounding wire. In explosion-proof environments, the requirements regarding grounding are very strict; furthermore, metal protection boxes also have requirements concerning the protective grounding of the enclosure.

This needs to be handled on a case-by-case basis; the regulations are quite clear.

Refer to the requirements of the gb-50257-2014 standard

The last edit to this post was made by liuyuqian on 2017-4-17 at 16:13. If it is a metal box, according to the GB 50093-2013 Code for Construction and Quality Acceptance of Automated Instrumentation Projects, grounding must be carried out in explosion-proof areas

For on-site grounding, it’s crucial to find a proper ground point; if the grounding resistance does not meet the requirements, or if there is no grounding device at all, then it’s better not to ground anything at all. However, most of the equipment on site has a grounding grid formed by connected galvanized flat iron strips. This grounding is intended to achieve equipotential grounding in order to prevent electric shock; equipotential grounding does not mean that there is no voltage present, but rather that the voltages are equal, so that touching the metal surface does not result in a voltage difference that could cause electric shock. Therefore, from a safety perspective, the metal box of the instrument and its metal enclosure should both be connected to this equipotential ground connection; this is also an effective measure to eliminate electromagnetic interference as well as induced electricity from lightning strikes.