CONNECTING SERVICE LINES. cont'd

TM 5-6640-214-14

WARNING

When the electrical power for the laboratory is to be supplied by a generator, the MAIN CIRCUIT

BREAKER must be in the ON position prior to starting the generator. The main power circuit

breaker SHOULD NOT BE SHUT OFF MANUALLY EXCEPT IN THE CASE OF AN EMERGENCY.

Turning the circuit breaker to the ON position when the power is already applied can result in

sparking which can ignite any combustible vapors which may be present in the laboratory.

After cabinets are positioned, electric conduits are connected by means of a 4-circuit terminal block between each

cabinet (fig. 2-6). Each electric conduit consists of 1 No. 8 R.H. wire and 3 No. 10 R.H. wires. After all electric

conduits of the cabinets are connected, they are then connected to the main power line within the laboratory.

When a unit of 6 cabinets is assembled, the surface-type panelboard with a 100-ampere main circuit breaker, eight 1-

pole, 30-ampere circuit breakers, and 140/220-volt alternating current must be used (fig. 2-6).

WARNING

Before proceeding, always keep in mind the WARNINGS listed in the front of this manual.

(1) Six-cabinet unit. Each unit of six cabinets is wired in exactly the same way. No. 1 wire is always the live

line in each unit, and No. 4 wire is always the neutral line. A 6-cabinet unit (fig. 2-6) is wired as follows:

(a) Mount the surface type panelboard at the center of the unit in order to feed three cabinets to the left

and three cabinets to the right.

(b) Number the cabinets 1, 2, and 3 to left and to right of the surface-type panelboard.

(d) Starting with third cabinet to right of panelboard, connect No. 1 wire to terminal No. 3 on second

cabinet; connect No. 2 wire of second cabinet to terminal No. 3 of first cabinet, and connect No. 3 wire on first cabinet

to circuit No. 3 in panelboard.

2-8