Breaker wiring

[carmusic]

Hi just wondering if the method of wiring in the left of schematic is ok for UL approval, i know it would be best to do the right schematic but i can't enter physically 2 10awg in same breaker!
my 16 awg wire is rated at 10amps

 

[rezer]

Hi just wondering if the method of wiring in the left of schematic is ok for UL approval, i know it would be best to do the right schematic but i can't enter physically 2 10awg in same breaker!
my 16 awg wire is rated at 10amps

What is the for? Your home?

 

[rjvh]

I don't know if it would acseptable for UL licensing but from technical point just my comment

you have 3 lines of 10 Amp protected to gether with a 30 Amp

yes, no objection if the load is a resistive one

if you have 3X a inductive load that is able to swich on simultainuasly than 30 amp will probably trip and 50 amp is needed for that occasion

Robert-Jan

Edit:
For wire sizing you have to calculate the voltage drop over a line

acording the NEC in a non comercial instalation 5% drop is allowed but check the code for that as europe have different tolerances (this means also with the start up of a inductive load)

 

[Willbe]

This guy helped me once

CustomerService_HAL_UL@us.ul.com

 

[carmusic]

it is for an industrial enclosure, of course my loads won't draw 10amp each, my point is is it ok to put small wire before the breaker or i must absolutely put a big wire that can handle all the current of the primary breaker?

 

[3v0]

If you do the left with 10AWG instead of 16AWG can you get the 3 10AWG wires into the 30 amp breaker ?

I do not know about code but it solves all the issues I can think of.

 

[Phasor]

my point is is it ok to put small wire before the breaker or i must absolutely put a big wire that can handle all the current of the primary breaker?

I'm not sure what your wiring rules are in the USA, but in Australia, the left-hand diagram would not be acceptable, but the right hand one would.

All conductors must be protected by a protective device of lower rating than the current-carrying capacity of the cable.

 

[Jakes21]

I would also say the right pic is better.its best too use a thicker wire than needed..using a smaller wire would cause heat that could be dangerous.

 

[3v0]

I would also say the right pic is better.its best too use a thicker wire than needed..using a smaller wire would cause heat that could be dangerous.

Reread the original post. He can not use the right pic because the wires will not go into the breaker.

 

[Willbe]

is it ok to put small wire before the breaker or i must absolutely put a big wire that can handle all the current of the primary breaker?

I think even the NEC will say that the downstream wire must only handle the current that the first upstream breaker trips at.
Otherwise there are many houses in the U.S. that are "unsafe".

 

[Phasor]

He can not use the right pic because the wires will not go into the breaker.

He hasn't mentioned what make/model of circuit breakers or switchboard he is using. If they are DIN circuit breakers, then small busbars are available, equivalent to 16mm2, to connect the tops of the breakers together.

 

[Analog]

The left diagram is against the NEC, because the 16awg wires are being tripped by a 30A device. The right diagram is also against the NEC, because a breaker cannot have more than one wire on its terminal.

The correct answer would be to bring a 10 awg wire down from the breaker, to a terminal strip, and then 30A wires to each of the next set of breakers.

 

[3v0]

The left diagram is against the NEC, because the 16awg wires are being tripped by a 30A device. The right diagram is also against the NEC, because a breaker cannot have more than one wire on its terminal.

The correct answer would be to bring a 10 awg wire down from the breaker, to a terminal strip, and then 30A wires to each of the next set of breakers.

Or if you can get 3 10 AWG wires into the 30A breaker it would be the same thing, which I suggested several posts ago. Yes/no ?

 

[rjvh]

Or if you can get 3 10 AWG wires into the 30A breaker it would be the same thing, which I suggested several posts ago. Yes/no ?

no normaly there is space for 2 wires if you install it according the rules and a third wire will push the pressure Plat/clamp not equal on the wire which can cause lossening of the whole conection over time (exspantion contraction) due to temparature differences

after that you have higer resistance so gets warmer and in very bad cases (no maintainance of checking the fasteners in a switchpanel) arc flash and all bad things from that

Robert-Jan

 

[rjvh]

Or if you can get 3 10 AWG wires into the 30A breaker

No you should not put more than 2 wires, normaly there is space for 2 wires if you install it according the rules.

A third wire will push the pressure Plate/clamp not equal on the wires which can cause lossening of the whole conection over time (exspantion contraction) due to temparature differences.

after that you have higer resistance so gets warmer and in very bad cases (no maintainance of checking the fasteners in a switch panel at time) you get arc flash and all bad things from that.

Robert-Jan

 

[rjvh]

something went wrong here I wasn't ready with my checking when this stated but the second post is the good version

Robert-Jan

 

[AlainB]

Hi just wondering if the method of wiring in the left of schematic is ok for UL approval, i know it would be best to do the right schematic but i can't enter physically 2 10awg in same breaker!
my 16 awg wire is rated at 10amps

Hi,

I would bring a 10awg wire from the 30 amp. breaker to a splitter box and, from there, another 10awg wire to each of the 10 amp. breakers. I would then be satisfied that it is safe. That is of course if it is possible to do it that way.

Alain

 

[carmusic]

Hi,

I would bring a 10awg wire from the 30 amp. breaker to a splitter box and, from there, another 10awg wire to each of the 10 amp. breakers. I would then be satisfied that it is safe. That is of course if it is possible to do it that way.

Alain

i think that's what i'll do with standard terminals block, i was looking for a bus bar to fit my breakers but it is 2-3 weeks delivery, no store keeps them!