what is sectional clearance in a switchyard layout diagram? (other than phase to phase and phase to earth)

 

Responding to Paul's Sep 15, 12:42pm query.... do a web search for NEMA Standard No. SG 6-2000!

Regards,
Phil Corso, PE {Boca Raton, FL, USA}
[[email protected]] ([email protected])

 

Hi Phil, did as you said but all searches led to IEEE website which I, not being a member cannot access. Help required

 

Responding to Paul's Sep 16, 2:28pm dilemma... contact me off-list!

Regards,
Phil Corso, PE {Boca Raton, FL, USA}
[[email protected]] ([email protected])

 

Sectional clearance is composed of the reach of a man, taken as 8 feet, plus an earth clearance. For the voltage at which the earth clearance is 8 feet, the space required will be the same whether a section clearance or an earthed barrier is used.

HENCE: Separation by earthed barrier = Earth Clearance + 50mm for barrier + Earth Clearance

Separation by section clearance = 2.44m + Earth clearance

For vertical clearances it is necessary to take into account the space occupied by the equipment and the need for an access platform at higher voltages. The height of the platform is taken as 1.37m below the highest point of work.

 

“Sectional Clearance” is the minimum clearance to be maintained in air between the live part of the equipment on one hand and earth or another piece of equipment or conductor (on which it is necessary to carry out the work) on the other.