Answer / amitava

Vacuum Circuit Breaker is a current interrupting device used in Normal and fault condition, can be used upto 66 Kv.
Load break switch is a on load Isolator, which breaks normal current, it has no arc quenching arrangement, no relays to sense faults, used upto 33 Kv.

Answer / azam

vcb operates in all conditions ( normal & abnormal
conditions) it has protective relaying, where as lbs
can b operated only in normal condition, it doesn't have
relay control ckt

Answer / ahamad kutty k.v.

Vacuum breakers are circuit breakers with vaccum as medium
of arc extingushing in place of oil or sf6 and usually
used for isolating a circuit
(specific equipment or portions of the
distribution system) and they can operate under faulty
condition also when detected by a protection relay. After
clearing the fault this can directly switched on to the
load without any change of blown out fuse which is the case
of a load breake switch.Load break switches are designed
to open
under full load only.in case of a fault the fuse of the
load breake switch will blew out and it should be replaced
before charging the circuit to the load.

Answer / amin

All of the above posts stating that the function is the
same are technically WRONG.

A Load Break Switch is designed to ONLY interrupt a circuit
under "normal" operating conditions. They are NOT or
intended designed to interrupt fault current! Even if
designed to automatically open (motorized), they must have
fuses in the circuit to interrupt the fault first and the
let-through current of the fuses must be coordinated to
stay below the load interrupt rating of the LBS.

A circuit breaker is designed to interrupt fault current,
and acts as an alternative to fuses. So a CB is both a LBS
and a Fault Interrupter.

Answer / michael von zechlin

Both can be used to isolate a load.

Both can have protective relays associated with them
although load breaks usually are fused for quicker
instantaneous isolation times (At or less than 3 cycles)

Vacuum breakers usually are used for isolating at a
switchgear (specific equipment or portions of the
distribution system) They make or break their circuit under
a vacuum. Load breaks normally do this in the air.

Load breaks have heavy contacts which are designed to open
under full load repeatedly.

Vacuum breakers can have the same but are normally not
except for vacuum contactors.

Answer / mahesh bial airport bangalore

vaccum circuit breaker is used in HT side.this breaker
having safety relays but in load break switch not having
any safety relays and it is not use in HT side it is used
in LT side only ( it is just like a ON,OFF switch )

Answer / akhil.goyalanager1985

vcb is only breaker

while load break switch is breaker+ isolator

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