The table below illustrates some of the new wiring practices recommended to achieve a high level of power quality. Many of the "before" practices are still reflected in building codes today.
| Old Practice or Code Minimum | Helpful Procedures or Current Recommended Practice | |
|---|---|---|
| Receptacle outlets per 20 amp circuit |
13 maximum | 3 to 6 maximum |
| Neutrals | Shared neutral, or even downsized neutral (on 3-phase systems) | Use double-size neutral or larger on 3-phase systems |
| One neutral shared among equipment (single-phase branches) | Use separate full-size neutral for each phase, back to panel | |
| Phase Conductors | Standard phase conductor sizing per Code | Use upsized phase conductors to minimize voltage fluctuations |
| Circuits & Panelboards | Can be shared among many outlets and uses | Use separate branch circuits for sensitive loads, emanating from separate panelboards, supplied by separate feeders (from separate K-rated transformers, if possible) |
| Grounding | Can use metal conduit as grounding conductor | Use separate insulated copper wire as grounding conductor |
| Downsized grounding conductor | Use full-size or upsized grounding conductor | |
| Grounding electrode system can consist of as little as a metal underground water pipe and an 8-foot ground rod | Use a copper ground ring (4/0 or larger ) and multiple interconnected ground rods to supplement the required electrodes in new construction | |
| Use a second ground rod if first measures over 25 ohms (no resistance measurement or further action is required) | Use multiple rods with a ground ring and measure before and after installation to ensure low resistance to ground (10 ohms or less is desirable, even less for certain sensitive applications, such as telecommunications facilities) | |
| Access floor used for equipotential grid in computer mainframe room | Use a copper grid system for equipotential grid | |
| No lightning or surge protection required | Use adequately sized lightning and surge protection systems | |
| Other Equipment | Standard-rated transformers, circuit breakers, and panels | Use harmonic-rated transformers and panels where electronic loads are present |
| Use standard-size neutral and ground buses in panel boards | Use 200% rated neutral and ground buses where electronic loads are present | |
| Circuit Breakers | Can use bolt-in or snap-in circuit breakers | Use bolt-in circuit breakers for more secure, reliable connections |