# divided circuit

Discussion in 'The Projects Forum' started by Lightfire, Feb 20, 2011.

1. ### Lightfire Thread Starter Well-Known Member

Oct 5, 2010
690
21
Hello,

I want to build a circuit which has a lot of sub-circuits.

Let's say it's looks like a electric company. Every houses has their own electric supply but all those supply are generally from the electric company. That's what I like to do.

I mean for example, sub-circuit 1 gets short-circuited, the other sub-circuits will not be affected. Just the sub-circuit 1 has the problem.

Is there any thing can make it true? What items do I need? Should every sub-circuit has this item? Or it is not possible to happened?

Thank you a lot!

Last edited: Feb 20, 2011
2. ### Lightfire Thread Starter Well-Known Member

Oct 5, 2010
690
21
Bump. Bump Bump

Apr 5, 2008
17,113
3,001
Hello,

There is no need to bump.
It has only been 4 hours from your last post.
It can take more than 24 hours sometimes as this is a worldwide forum.

The sub circuits can have small fuses that will blow to protect the main circuit.

Bertus

4. ### Lightfire Thread Starter Well-Known Member

Oct 5, 2010
690
21
how big is the small fuses are????

5. ### SgtWookie Expert

Jul 17, 2007
22,194
1,763
You need to decide what amount of current is a reasonable maximum for each circuit, and then choose a fuse that will open if the maximum is exceeded.

The wiring between the supply and the circuit must be rated for higher current than the fuse, or else the wiring could melt or catch on fire.

The fuse must be rated for the voltage that it must interrupt.

6. ### Lightfire Thread Starter Well-Known Member

Oct 5, 2010
690
21
For example,

my circuit was rated as 240 volts then i must use electric wire that is about 300 volts, right? and i must use 240 volts fuse??????

7. ### beenthere Retired Moderator

Apr 20, 2004
15,815
290
The fuse must be rated to clear at 240 VAC. Insulation must be able to handle greater voltages. The line is measured in RMS, which is a measurement that allows a comparison with DC. The peak voltage will be more like 340 volts (the fuse will have this taken into account). So your insulation needs to be for greater than 340 volts. 600 volts is probably better.

8. ### Lightfire Thread Starter Well-Known Member

Oct 5, 2010
690
21
what if my circuit was all rated as 12 volts (i mean any devices were 12 volts), what fuse should i use?

9. ### dribron New Member

Feb 22, 2011
3
0
Well you will need to calculate you current. It isn't enough to just go by your voltage needs, you will need to know your current, otherwise you'll be blowing fuses.. And possible creating a rather dangerouse situation.