Barriers are required in service switch boards to provide the physical separation between the load terminals and the service busbar and the terminals:

De-energizing the load side of the switchboard by operating the disconnecting means will de-energize the ungrounded service conductors:

Horizontal travel of conductors through more than one section of the multi section switchboard is necessary where a raceway or cable entry is made into the switchboard section other than one at which the conductors are terminated

Each Switchboard if used as a service equipment, shall be provided with a main bonding jumper

The high leg is common on 3-phase and 4 wire delta system and is typically designated as:

When a ground fault occurs on 3-phase ungrounded system, the voltage to the ground on a ungrounded system may be equal to line to phase voltage

For ungrounded system above 600V and below 1000V Ground Fault Detectors shall be provided for warning purpose

All the switchboards and panelboards supplied by the feeders in two family dwelling shall be marked to indicate the device or equipment where the power supply originates:

Circuit directory is important feature for safe operation of an electrical system under normal and emergency conditions

Minimum space between the bottom of the enclosures and non-insulated busbars entering the switchboards or floor-standing panel-boards is:

In switchboards or panel-boards unused openings for circuit breakers and switches shall be always closed using identical enclosures

Over-current protective device shall be located at the supply side of the panel board

Relays and Meters located on the swithboards shall always be grounded:

___ is the minimum space required to be provided between the top of the switchboard (not totally enclosed) and any combustible ceiling

Panel-boards equipped with snap switches of rating 30 amps or less shall be provided with over-current protection of not more than _____

When a transformer supplies power to panel-board, the over-current protection shall be located at __ side of the transformer

A delta breaker shall not be installed in panel-board

Fuses installed as part of service equipment in panel-boards shall be permitted on the load side of the service switch