Hello AAC community
Not sure i posted this under the right forum but I'll go ahead and see the reaction. If a 4 pole breaker is rated 25A does it mean i can connect 4 single 25a load to each pole or my entire load must not exceed 25A ?

 

I've never heard of a 4-Pole Circuit-Breaker.
Can You provide pictures and/or part-numbers ?
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Hello AAC community
Not sure i posted this under the right forum but I'll go ahead and see the reaction. If a 4 pole breaker is rated 25A does it mean i can connect 4 single 25a load to each pole or my entire load must not exceed 25A ?

A four-pole breaker would be three-phase plus neutral. It is guaranteed not to trip when all four circuits are at 25A. As with all breakers, it will probably trip when any of the circuits exceeds about 40A or 50A - see the curves in the datasheet.
Normally, it would have a reasonably balanced three-phase load, such as a three-phase motor.
[Edit] It is normally made as four single-pole breakers with a linking bar that forces them all off if one trips, although it may all be encased in one enclosure.

 

I've never heard of a 4-Pole Circuit-Breaker.
Can You provide pictures and/or part-numbers ?
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They are pretty common in 3-phase systems, they are used where you need to break all 3 phases and the neutral.

 

This may be done in some countries, but not in the USA.

Neutral-Conductors are normally connected to Ground,
which means that You would never want it to be "Fault-Current-Limited" since
any of the 3-Phases could possibly come into contact with the frame of the Machine,
or directly to the Neutral-Conductor.
Under these circumstances,
if the Neutral-Circuit-Breaker trips,
the Frame of the Machine could remain HOT, with no Personnel-Protection.
This can also create Voltage imbalances for
any Single-Phase-Control-Circuitry in the machine,
possibly resulting in damage to the machine.

The only time it is permissible to "switch" the Neutral is with
a specially-designed "Safety-Disconnect-Switch", ( NOT a Circuit-Breaker ),
mounted near, or on, the machine.

The Neutral should normally never be switched at the Distribution-Panel,
but only at the connection to an individual machine.

There may be certain strictly-defined exceptions for
some specialized-Industrial-Environments such as Mining, Marine-Shore-Power, etc..
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We normally switch neutral (to eliminate a dual ground to neutral bond) when we have separately derived power systems switching.
https://www.ecmweb.com/content/article/20886620/separately-derived-system

If you wish to use a separately derived system, you must use a 3-pole transfer switch for a single-phase, 3-wire system, or a 4-pole transfer switch for a 3-phase, 4-wire system [Art. 100 definition and Sec. 250-20(d) FPN No.1].

https://www.ecmweb.com/national-ele...ing-and-bonding-of-separately-derived-systems

 

I came across such a breaker in a non-isolated driver for a DC motor system. The purpose was dual, it would either trip because of an overload and remove power from both the armature and the field, thus protecting the motor, or it would trip if any of the four motor leads contacted the mains neutral, protecting the driver.
It also provided isolation of the motor connections for any service person who did not disconnect power from the driver while working with the connections, although that was not the intention, I am sure.
This was quite a few years ago, visiting a plant that I am sure the OSHA inspectors never were aware of, and never visited.

 

I've never heard of a 4-Pole Circuit-Breaker.

This may be done in some countries, but not in the USA.

But yet they sell them at your local Lowes store. They are an available thing to extend the circuits in a too small breaker panel. They also make and sell twin breakers for two circuits in one slot.
https://www.lowes.com/pd/Eaton-Type-BR-20-Amp-4-Pole-Quad-Circuit-Breaker/3009418

 

There are cases where systems have multiple separately derived system AC power sources. In these cases the neutrals need to be kept seperate. Recently had a machine installed that would not start correctly. It seems they just split the main feed (large 3-phase breaker/disconnect) to the CVCF (UPS Power on the smaller 3-phase breaker) instead of pulling a separate isolated power feed. The easy fix, jumper the panel neutrals because there was only one power source.

 

The 4-Pole-Breakers sold at Lowes are NOT "Common-Trip" Breakers,
they are for cramming more 2-Pole, 240-Volt, Circuits into a
Panel that was sized too small to begin with.

Lowes has absolutely zero Circuit-Breakers designed for
3-Phase-Legs plus a Neutral, that is also "Common-Trip".
This would be a "Special-Order" item anywhere in the USA.
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If a 4 pole breaker is rated 25A does it mean i can connect 4 single 25a load to each pole or my entire load must not exceed 25A ?

Most of us think the 4th pole is for neutral. You have 3 hot outputs. You can have three 25A loads if you are connecting line to Neutral. In the US that is three 120V loads. You could also connect Line to Line and have less outputs at 220V.
imo

 

You should only Power a 3-Phase-Load with a "Common-Trip" Circuit-Breaker.
( 3 or 4 Poles )
Individual Breakers should be used for "Single-Phase" ( Hot plus Neutral ) Loads.
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You should only Power a 3-Phase-Load with a "Common-Trip" Circuit-Breaker.
( 3 or 4 Poles )
Individual Breakers should be used for "Single-Phase" ( Hot plus Neutral ) Loads.
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Then show me where the TS stated his breaker is 3phase. 3phase wasn't brought up until post #3 then everyone ran with that. The TS still hasn't been back with what type breaker he has. And his asking about what load each individual breaker/switch is good for makes my answer as good as all saying 3phase, since he never mentioned common trip.

 

I have a similar breaker, except mine is 15 amps, 250 volts, marked "special purpose, not for general use." Each of the poles are much larger than a "standard" sized residential/commercial breaker that I am familiar with. Made by Heidemann, so clearly they are good quality. The connections are via threaded studs on the rear and so it is clear they will not go into a distribution panel. Probably the non-isolated DC motor driver that I mentioned earlier.