If your load is 20a at 230v do you need a 20a breaker?

If your load takes 20 Amps then: * a breaker with a smaller rating - say 15 Amps - would always switch off the current because it is too high for the breaker to carry

* a breaker with a 20 Amp rating could be safe to use with this load, but it is so close to its rated limit it may keep tripping to switch off the current.

If that happens it may be better to use a breaker with a slightly higher rating - say 25 or 30 Amps - but do not decide to change it yourself unless you are an experienced electrical technician.

* A breaker with a higher rating - say 40 Amps - may not switch off the current if a fault develops in the 20 Amp load so it could be unsafe to use.

The likely overall current - and the kinds of loads (whether they are include any motors or if they are only heating and lighting) - from all appliances that are likely to be plugged into the circuit which the breaker has been installed to protect must be properly considered and any Fire or other safety hazards must always be assessed. ALWAYS CHECK WITH YOUR LOCAL WIRING SAFETY OFFICE BEFORE YOU ATTEMPT TO CHANGE ANYTHING - BREAKERS, CABLES OR OUTLETS -

ON A POWER MAINS CIRCUIT

IF YOU ARE NOT ALREADY SURE YOU CAN DO THIS JOB

SAFELY AND COMPETENTLY

REFER THIS WORK TO QUALIFIED PROFESSIONALS.

If you do this work yourself, always turn off the power

at the breaker box/fuse panel BEFORE you attempt to do any work

AND

always use an electricians test meter having metal-tipped probes

(not a simple proximity voltage indicator)

to insure the circuit is, in fact, de-energized.