Recent questions tagged underground

Description : Where have all the fire hydrants gone?

Last Answer : I have a yellow one in my yard. My house insurance was discounted because of that.

Description : Draw and explain the construction of underground cables. 

Last Answer : Underground cables:   OR Explanation:- i) Core or conductor: * It function is carry current. * Cable may have single or more than single core conductor. * Conductor ... handling of cables. * It is similar to bedding & consists of fiborous material such as jute. 

Description : Differentiate between overhead transmission and underground transmission.

Last Answer : Points Overhead line  Underground cable Capital cost  Less More Erecting cost  Less More Time require for completion of work Less More Flexibility More ... Space consumed Space consumed  No space consumed Appearance Not good  Very good 

Description : State the procedure for laying / installation of underground cable.  

Last Answer : 1) Direct laying Cable: or Trench laying method: Procedure: * For laying of a cable trench about 1.5m deep and 0.5m wide is made along the cable route. * A ... over. * Cables laid in this manner are usually plain lead covered because troughing affords good mechanical protection. 

Description : Why don't we burry power lines underground ?

Last Answer : Because conductor used for power transmission are not insulated and if we do so it create phase to ground fault causing interruptions to supply.

Description : Why underground service connections are service connections are costly than overhead service connection

Last Answer : Reason: Underground service connection is given by underground cable. This cable is costly than bare conductor. Sometimes cable trench is required for cable laying, which requires additional cost. So underground service connections are costly than overhead service connection.

Last Answer : The underground system cannot be operated above 66 kV.

Description : what is the use of bedding on underground cable?

Last Answer : Bedding is the layer above the lead sheath it protects the lead sheath from corrosion that means it gives chemical protection to metallic sheath(lead sheath)

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