Specifications

35
Schneider Electric
Summary
Essential rules
b Make sure all exposed conductive parts have the same potential..
b Choose equipment that complies with standards.
b Follow manufacturers’ instructions.
b Protect your installations from outside disturbances (careful
grounding of shielding).
b Eliminate ground loops.
b Shield both sensitive and interfering cables.
b Use enclosures or cubicles as Faraday cages (contact between
unpainted, rust-free steel sheets, short and wide earth braids, no
unnecessary openings, etc.)
b Do not use "pigtails" or long grounding wires.
b Avoid TN-C systems, as common mode interference is the
principal problem in EMC.
b Clamp conductors against ground planes.
b Separate conductors by category.
b Do not leave any conductors unconnected.
b The outgoing and incoming conductors should always remain
together.
b Make use of "natural protections" (cable raceways, etc.)
Lack of regard for rules can lead to:
b Problems with EMC:
v operating problems:
- evaluation of the installation,
- re-cabling,
- implementation of software solutions.
v risk of service interruptions,
v systems that do not perform their tasks.
b Loss in production, expertise, need to re-do work, high costs.
Cabling Guidelines