Hi all.

if my HDB home is fitted with a 40 amps main switch, and i plug in a 20A electrical appliance into a wall socket, will it cause any failure or trip?

so if i plug into P4 is it ok, since P4, P5 & P6 is 32A MCB, it should not trip right?

Thank you

Edited March 27, 201313 yr by runbird

If plug in 20A appliance into P4, since P4 is protected by a 20A SP MCB, it will not trip.

However, P4 also supplies to Powerpoint1 to Powerpoint10 (PP1 to PP10).

Non of these other powerpoint can be in use when the 20A appliance is on.

Any overload will cause the 20A SP MCB to trip.

Be sure to change the fuse of the 20A appliance to a 20A one.

Be sure that the cable to the 20A appliance is 3CX76.

If plug in 20A appliance into P4, since P4 is protected by a 20A SP MCB, it will not trip.

However, P4 also supplies to Powerpoint1 to Powerpoint10 (PP1 to PP10).

Non of these other powerpoint can be in use when the 20A appliance is on.

Any overload will cause the 20A SP MCB to trip.

Be sure to change the fuse of the 20A appliance to a 20A one.

Be sure that the cable to the 20A appliance is 3CX76.

Hi yoongf,

should be 32A SP MCB? or 20A MCB? from the pic, it should be 32A MCB for P4 to P6? am i right?

since it is a 32A MCB, then why there is a 13A S/S/O in ring circuit at the PP1 to PP 10? what does it mean?

Thank you

Opps.. my bad.. the P4 to P6 is protected by 32A SP MCB each.

Each powerpoint socket is rated for 13A only. The metal contacts, springs, all designed for a 13A load. Those meant for 15A (round 3pin holes).. have bigger contacts, springs etc.

In all the design, there will always be a gradual drop in rating as u move further away from the Mains. Any fault wil result in a gradual escalation of the tripping design. This will help in troubleshooting shd a fault occur. Also, to install all powerpoint at the max rating is very costly.

Opps.. my bad.. the P4 to P6 is protected by 32A SP MCB each.

Each powerpoint socket is rated for 13A only. The metal contacts, springs, all designed for a 13A load. Those meant for 15A (round 3pin holes).. have bigger contacts, springs etc.

In all the design, there will always be a gradual drop in rating as u move further away from the Mains. Any fault wil result in a gradual escalation of the tripping design. This will help in troubleshooting shd a fault occur. Also, to install all powerpoint at the max rating is very costly.

Hi Yoong,

so is it alright if i plug in my 20A appliance into this 13A wall socket? will it cause anything?

Thank you