Telsa, perhaps you need to read the section titled “Disadvantages of IG Wiring Techniques”, they far outweigh “The Benefits of IG Wiring”. To make IG beneficial, they have to be on a single dedicated circuit, installed in conduit, the only circuit in the raceway from origination to the equipment end, use a manufactured cable made for IG, and used on stand alone equipment not interconnected to anything.
I cannot recall any installation that meets all that criteria. The only situation I can think of would be a home A/V or PC system where all the components are powered from a duplex or quad receptacle. If you were to install two dedicated IG circuits and interconnect the equipment, like you would in a data processing environment, you have compromised the IG system period..
As I stated before the only purpose of an IGR is to prevent common mode noise. It cannot clean or eliminated common mode noise. Only a SDS like a transformer, balanced power, or dual conversion UPS can do that. Do not know of many home owner’s who can afford to spend as much or more for one of these systems that their PC cost them.
I design data centers, telephone office power, and protective grounding system. We do not use IGR. We use dual conversion UPS and DC battery plants on SG circuits to provide clean uninterruptible power. We are starting to use balanced power systems in conjunction with the UPS which eliminates harmonic distortion and all ground problems associated with grounded circuit conductors, be eliminating the neutral altogether for single phase loads (120 VAC).
[This message has been edited by dereckbc (edited 07-27-2004).]
