Electrical Safety

High Voltage - Hall A does not have any exposed high voltage leads. The dipole and large quadrupoles are typically low voltage 10V, 2000A while Q1 is 5V, 3500A. A plexiglass cover to preclude shorting out and melting tools surrounds all exposed leads. Photomultipliers which typically run at a kilovolt are in the detector hut and use standard HV connectors (SMA's) which lessen the shock hazard. Ion pump power supplies operate at upward to 5 kV; and also use SMA's.

As a general principal the following is done on all electrical systems.

1.

UL ratings are required for all AC/DC power cables

2.

Ground Fault Interruption (GFI) is at the substation that feeds the main power panel. GFI is on for 120V utility outlets throughout the hall.

3.

There are four (4) heat detectors at top of the Hall A dome that signal the MCC, which then enables the water fire suppression system. We use the VESDA system in Hall A, and we have smoke detectors in shield house instrument racks which shuts off power.

4.

The shield house detectors are equipped with clean agent fire suppression systems.

5.

All control wires meet the vertical wire test VW1 and UL 1581.

6.

All DC Power Cable such as 535,300 mcm meets or exceeds the flame test requirements of MSHA, IEEE, ICEA and UL. They also meet the following requirements: ICEA S-68-516, NEMA WC-8, ICEA S-19-81, NEMA WC-3, MSHA-P-123, UL listed as shipboard cable, and they meet IEEE flame test of 70,000 BTU/hr. The #2 Welding Cable meets the UL vertical flame test per UL 854 and MSHA-P-123-141.

AC Power Cables

Type G 4/0 4 conductor met the following classifications: MSHA-P-123, ICEA S-68-516, NEMA WC-8 ICEA S-19-81, and NEMA WC-3.

7.

Magnetic Fields - All of the Hall A magnets (quadrupoles Q1, Q2, and Q3) have iron. The dipoles are iron dominated magnets and the stray field on all are on the order of a 100 gauss level.