for free standing units. Make sure you mark the panel indi- cating which circuit breaker or fuse protects the cooktop and which circuit breaker or fuse protects the oven. If none of the factors are present that require two individual branch circuits for the sectional range, one branch circuit may be installed and “tapped” in a junction box to provide power to each piece of sectional range. Figure 33 shows such a configuration. Before installing any branch conductors or devices, always check the nameplate load rating on the specific equipment to make sure that all circuit components
Wiring Electrical Circuits 73 meet or exceed the requirements of the NEC. When connect- ing a sectional range using the single-branch circuit method, the electrician will normally run a 50-ampere-rated conduc- tor from a double-pole circuit breaker in the panel, to a centrally located junction box, convenient to both the cooktop and the oven. An example of this is shown in Figure 33. The electrician will then tap or connect from this junction box with two separate load-rated cables to both the cooktop and the oven. Always check the nameplate on each piece of equip- ment. This determines what size conductor you should install to each piece of equipment from the main branch-circuit junction box. Normally the conductors to each separate cook- ing unit will be smaller in size than the conductor used to feed the main circuit, since this main circuit is based on the total of the loads of both pieces of equipment. Connecting the equipment to the tapped circuits may be accomplished by using the proper receptacle and pigtail or by direct connec- tion into the manufacturer-supplied junction box. Labeling the cables in the junction box with what appliance they supply is also a good practice. JUCTION BOXES 50-AMPERE 3-WIRE 240-VOLT DOUBLE-POLE CIRCUIT 120/240- VOLT SUPPLY WALL-MOUNTED OVEN COUNTERTOP COOKING UNIT (STOVETOP) FIGURE 33—This shows the connections for a sectional range using one branch circuit.
Wiring Electrical Circuits 74 Water Heaters In connecting residential water heaters, it’s common practice in the electrical trade to use a two-wire, No. 12 cable, with a grounding conductor. Be certain the nameplate load rating on the water heater doesn’t exceed the ampacity of the No. 12 cable. However, when wiring in this manner remember that the conductor colors in a No. 12 cable are usually black and white, which requires the electrician to re-mark the white conductor with black tape or paint it at any point where the white con- ductor is accessible or visible. This is to prevent someone from mistaking it for a grounded conductor. The grounding con- ductor, usually a bare copper conductor, must be connected to the frame of the water heater. The equipment manufacturer usually provides a green terminal screw located inside the junction box for this purpose. Figure 34 shows a diagram for a standard two-element water heater. Notice that the water heater doesn’t require a grounded conductor, or neutral, to operate properly. Also noted is that the disconnect
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