I am going to install a 3 phase 100 amp circuit breaker panel board to provide service to 9-10 individual air conditioning units. how do i wire these services?

In a traditional North American residential electrical panel (120/240 volt, single phase), installing a single width or single pole circuit breaker, you would expect to read 120 volts from the breaker terminal screw to either ground or neutral. A double width or double pole breaker would provide 120 volts from either of the breaker terminal screws to ground or neutral AND it will provide 240 volts BETWEEN the TWO breaker terminals.

A single-width circuit breaker case that contains two handles is NOT a two pole circuit breaker (these are called "tandem" or "1/2 size" breakers). This is because a single width breaker engages only one "line" in the panel. A double width breaker will engage 2 "lines" as a triple width breaker would engage 3 "lines" of a 3 phase panel. A single wide breaker can not physically engage more than 1 "line" so it will never be able to pass 240 volts.

You must install a double width / double pole breaker to safely supply a 240 volt circuit / device.

Total amp rating of breaker.
Total amp draw across all three hot wires.
If one leg is weak or gets hot enough to exceed heat rating of breaker, the breaker will trip all 3 poles.
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Hi - I'm an electrician and can help you with your question.

A BR2100 circuit breaker is a 2 Pole 100 Amp (for the part number "BR2100", the "2" indicates the number of poles and the "100" indicates the amperage) circuit breaker. It can be installed in a single phase or three phase 120/240 VAC system panel that specifically lists the BR series breakers as acceptable for use.

A BR260 A BR2100 circuit breaker is a 2 Pole 60 Amp (the part number BR260, the "2" indicates the number of poles and the "60" indicates the amperage) circuit breaker. It can be installed in a single phase or three phase 120/240 VAC system panel that specifically lists the BR series breakers as acceptable for use.

It is not possible to have a BR2100 rated for 60 amps, 1 or 3 poles, or a BR260 rated for 100 amps, 1 or 3 poles.

It is not permissible to install any circuit breaker brand or type in any panel that does not specifically include it on a list of acceptable circuit breakers.

Circuit breakers are designed to carry 80% of the amperage rating.
To determine the load a circuit breaker can carry, multiply the circuit breaker amp rating by 80%. This means that if you need to supply more than 80 amps, you cannot use a 100 amp circuit breaker. A higher rating is required. A BR2110 would be acceptable for loads greater than 80 amps, but less than 88 amps because the formula above says: 110 amp x 80% = 88 amps.

To determine the breaker size, determine the load (by measuring with a meter or obtaining amp rating of the load from the data plate) and multiply it by 125%. Using the same numbers in the example above; assume an 88 amp load. 88 amps x 125% = 110 amp circuit breaker. The 60 amp breaker is acceptable for up to 48 amps because 60amps x 80% = 48 amps. A 48 amp load needs a 60 amp breaker because 48 amps x 125% = 60 amps.

I hope this helps and good luck!

Hi Pauline, I'm an electrician and can help you with this problem.

The only breakers that are permitted to be installed in any circuit breaker panel are listed inside the door on the label. Introducing any other type or brand is a fire hazard and a code violation. The national electrical code is very clear on this.

If you need to provide a GFCI protected circuit from this panel, you'll probably need to install a smaller panel from this panel - called "sub-panel" of a brand and type that will accept a GFCI circuit breaker. This is done by purchasing a 2P20A GFCI breaker and a smaller circuit capacity / ampacity panel rated for the same voltage as the main panel. You'll also need a ground terminal strip for this panel, too. A 60A main lug panel with 8 or more circuits type panel might be a good place to start. Purchase a 2P circuit breaker with an ampacity no greater than the sub panel is rated at - in my example - a 2P60A would be right. You may use a smaller breaker (2P40A or 2P50A) if you wish - but none greater. Mount the sub panel in a location near the main panel. Remove and discard the bonding screw or lug (if provided and installed already) that may connect the neutral bar and threaded into the panel enclosure. Install the ground terminal strip you purchased separately into the threaded holes provided for it inside the panel enclosure. Install the Ground symbol sticker next to this bar. Run a 4 conductor cable, pipe & wire, etc. feeder sized for 60A based on the location, temperature, etc. between the main panel and the main lug panel. Terminate the cable the sub panel end as follows: black & red or "hot" wires into the the lugs that are connected to the bus bars, white or "neutral" to the neutral bar and the bare or green "ground" wire into the ground terminal strip you installed previously.

Next terminate the other end of the cable. Power off the main panel completely. Terminate the white neutral and the bare or green cable in the neutral bar in separate terminals. Install only one wire per terminal - do not "double up" wires under a single screw. If there is a separate strip for neutral and separate strip for ground - maintain neutral wires to neutral strip and ground wires to ground strip. Also, do not intermix ground and neutral wires in the others terminal strips! Install the 2P60A breaker in an unused space in the main panel. Connect the two hot wires to the breaker terminals. If using aluminum wires, be sure to clean and apply oxide inhibitor to stripped ends of the wires.

Now, you should have a smaller panel with 8 or more empty spaces for circuit breakers that will become live when the 2P60A breaker is in the main panel is turned on. With it still off, install the 2P20A GFCI breaker in the new sub panel. Run your circuit(s) to this panel. Connect them as usual - but any neutral and ground wires installed must be terminated in their respective terminal strips. As mentioned above, never install them in the others strip.

If installing in a 3 phase environment - you may wish to install a 3 phase sub panel so that 3 phase loads can be connected to it. This will require a 3P60A breaker and 5 wires instead of 4 wires to be run between the two panels. The additional wire would be a hot and blue in color for a 240/208/120 panel.

I hope this helps & good luck!

This work requires a license (or qualified person) everywhere that the National Electrical Code is enforced.

If you're asking how to wire a single phase 200 amp panel from a larger, 3 phase panel of the same voltage - ONE way is to install a 2 pole - 200 amp breaker into the 3 phase panel. Provide 4 correctly sized conductors with the correct insulation in a cable or conduit between the 3 phase panel and the 200 amp single phase panel. Two of these conductors should be black and red (for 120/208 volt system) and connect to the 2 pole - 200 amp circuit breaker terminals, the third should be white and connected to the neutral bus bar. The forth should be green and is connected to the neutral bus bar as well but *only if* it is "service equipment" If it is a "main or sub panel", the green wire should be connected to the ground bus bar. The other end of the conductors should be terminated in a "main lug only" 200 amp panel. The back and red connect to "line 1" and "line 2" bus lugs, the white to the neutral bus bar that is NOT electrically connected to the panel enclosure (do not install the screw or strap between the bar and enclosure). The green must be connected by installing a separate bar that is securely fastened both mechanically and electrically to the enclosure for ground connections.

There is a great deal going on here - and plenty of variables that can change how to do this work, safely and correctly. This is an example of just ONE of many different ways to do the work for a particular installation. There is no one way that works for all situations. If your situation does not support this method - you will have an unsafe installation and subject the building and people in it to a dangerous fire / safety hazard.

Please, consult a licensed electrician before attempting this work.

The breaker that feeds the panel and the wire are what determines the rating. The panel has to be at least as high as the breaker. It can be more, and no problem.The problem I see is that the wiring is undersized for the 60 amp breaker. You should have #6 wires or change the breaker to a 50 amp. If that is not enough for your load, you must change the wiring. It also depends on the type of wire. THHN will have the largest amperage, but if it is TW, it will be lower. Rule of thumb would be #10-30 amp, #8-40-50 amp, #6-50-60 amp, #4-70-90 amp and #2-95-135 amp. There are other factors, such as derating etc. but if you wanted to increase to 100 amp, I would run #2 thhn. Hope this helps.

yes,if it has worn the insulation through on one or more of the hot phase conductors to the neutral phase wire,but also check the neutral busbar in the breaker panel for a high resistance connection as this will also trip the main breaker

the 1 and 3 poles, the 2nd is used for more a 3phase system, hooking up say 1 and 2 wont give you 120v. test with a volt meter to confirm but if your looking for 240 you need to use 1 and 3

Sounds like you have a bad capacitor for your squirrel cage fan , now as for the a/c unit sounds like you have a direct short in compressor to ground or leg to leg , check all wiring to make sure that it is not grounding out or melted together.

WITHOUT ANYTHING TO LOOK AT I WOULD SAY HE CONNECTED HALF THE LOAD TO ONE OF THE PHASE WIRES AND THE OTHER TO THE OTHER PHASE WIRES , PHASE WIRES MEANING 120/240 SINGLE PHASE , SO IF THAT IS THE CASE TAKE THE WIRES HE HAS BUNDLED TO ONE PHASE OR ONE TERMINAL ON THE BREAKER AND THE OTHER TO THE OTHER TERMINAL OF THE BREAKER IN SOME CASES IT IS NECESSARY TO CONNECT THE WIRES WITH CONNECTOR, APPROVED TYPE AND THEN TO THE BREAKER TERMINAL ,THIS JUMPER SHOULD BE RATED THE RATEDING OF THE BREAKER YOU ARE INSTALLING ,GOOD LUCK