# How much load can a 4mm copper wire handle.

Discussion in 'General Electronics Chat' started by Sundeep Kumar, Jun 3, 2015.

1. ### Sundeep Kumar Thread Starter New Member

Jun 3, 2015
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0
I'm not much in this before but I want to know that how much load (in kw) can a 4mm copper wire handle.
Here are some details about wire I am using.

Flame Retardant FR PVC Insulated Industrial Cable Copper Conductor 1100 Volt
Number/Nom. Dia of wire mm = 56/0.3
Thickness of insulation = 0.8mm
Resistance (max) per km at 20 degree centigrade = 4.95 ohms

Current carrying capacity 2 cable single phase
In conduit trunking = 24amp
In unenclosed clipped direct to a surface or on cable trays = 29 amp

Well any kind of help will be appreciated.

2. ### MaxHeadRoom Expert

Jul 18, 2013
10,851
2,521
One element missing is the actual operating voltage?
Max.

3. ### Sundeep Kumar Thread Starter New Member

Jun 3, 2015
4
0
Thanks for reply max. It's 220 volt.

4. ### Kermit2 AAC Fanatic!

Feb 5, 2010
3,851
966
current (squared) times resistance

(24 x 24) x 4.95 = 2.85 kilowatts of loss which will appear as HEAT along one kilometer of your cable.
Volts times Amps is power you have applied
220 x 24 = 5.28 kilowatts

you will suffer approx. 50% loss using one kilometer of your chosen wire to carry the stated voltage and current

Sundeep Kumar likes this.
5. ### dl324 Distinguished Member

Mar 30, 2015
3,377
651
90-100 amps for chassis wiring. Lower for power transmission. These are conservative numbers and you should consult local electrical codes.

Wire is generally rated in current capacity. Maximum voltage is determined by insulation.

6. ### Sundeep Kumar Thread Starter New Member

Jun 3, 2015
4
0
Thanks for the info kermit2. Correct me if I'm wrong as written on the wire it's a 1100 volt wire then why don't we multiply 1100*24 instead 220*24

7. ### gerty AAC Fanatic!

Aug 30, 2007
1,154
304
1100 is what it's capable of carrying, that's not what you are using though.

8. ### Sundeep Kumar Thread Starter New Member

Jun 3, 2015
4
0
Dwar gerty if I use the same wire in some country where operating voltage is 110 volt then by using above equation wire capicity will change. How can this be happen.

9. ### Kermit2 AAC Fanatic!

Feb 5, 2010
3,851
966
loss formula is CURRENT squared.

The lower voltage requires higher level of current for same watts. 220 volts and 1 amp gives 220 watts of power. If you lower the voltage to 110, then you must send 2 amps to get 220 watts.

Aug 30, 2007
1,154
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11. ### Stuntman Active Member

Mar 28, 2011
189
50
How much can it deliver?

It CAN deliver

P=V*I
V=1100V (I have to assume this is AC wire rated for RMS voltage)
I=29A (I have to assume you are using open raceways)

P=31.9KW

Anything other than this is constraints of your application:
What RMS voltage.
What kind of raceway?
Are you worried about total power delivered? If so, wire length comes into play (and you will most likely need a return path)

Yes, a grid using higher voltages can deliver more power through the same wire.