Can I use two 30A breakers together for a 60A water pump?

Question

I have a 240v water pump connected to a 60-amp 240v breaker. Can I use two 30-amp 120v breakers pinned together in place of the 60-amp breaker?

Answer 1

No, and the level of "not understand what you are doing" is concerning.

60A at 240V (220 is at least 50 years out of date) is also 60A at 120V, twice. Two 30A 120V breakers are exactly equivalent to a 30A at 240V breaker in terms of "size" but the 240V breaker ensures "common trip" which is desirable from a safety point of view.

Any replacement breaker must be UL-listed for installation into the panel in question - the same brand and model, or one that has been specifically tested and listed as being compatible with that panel - "it fits" is not nearly good enough, and problems from non-compatible breakers could get ugly fast with 60A breakers (lots of power available to melt poorly fitting connections typical of using the wrong type of breaker.)

Pretty sure you won't be finding any 60A at 120V breakers to pin together, so just get the correct breaker if you need to replace the breaker. Of course if the problem is with the pump or wiring rather than the breaker, throwing parts at a problem only solves it if you happen to throw the right parts.

Answer 2

The right breaker is $12.

(I'm being generous here) you are confused about how 120/240V split-phase works. A lot of people think you multiply amps by 2 when going from 1 phase to 2 phases, or the other way around. Not at all.

The different phases and neutral simply let you pick the voltage - 120V vs 240V. The amperage is exactly what it says on the tin - a 30A circuit uses a 30A breaker, a 60A circuit uses a 60A breaker. Which are $12 by the way.

Yes, it's a double breaker, but really, all circuits could be double breakers. We just don't bother putting a circuit breaker on neutral wires, so in North America that means 120V circuits get to use single breakers.

But yes, you can handle-tie singles to drive 240V-only loads.

You need to use an approved handle-tie, not a nail. They are $3. But yes, you can take two 30A 120V breakers and make a 240V breaker, it will be a 30A breaker though lol.

This does not work for 120/240V loads which include a neutral wire, such as dryers or ranges, which require a feature called "common trip" (one side trips, all do). Why not?

Because the handle-tie is only for the protection of maintainers. To make sure the maintainer turns off the whole circuit and doesn't leave half of it energized out of unawareness.

Handle-ties do not provide common trip because breakers are designed to "trip free", i.e. trip even if the handle is held in the on position. Such as by a locking kit, that you might put on a fire alarm breaker. Yeah, that's legit.

Answer 3

No you should not.

1. It increases the risk of failure. There would be 2 components that could fail instead of 1. And no matter how they are connected they will be working outside their intended scope.
2. The functionality achieved with 2 breakers would be different than expected with 1 breaker. It is uncommon to be expected to operate 2 breakers instead of 1 for such a pump. This could expose equipment, and people to risk.
3. It would be against regulations / standards in many countries. There are specific regulations regarding breakers and cables for AC loads connected on the grid. There is a lot of science and experience built into these regulations and standards.

Answer 4

This is a single phase, 240V pump rated at 60A or Max 60A?

You should check the manufacturers documentation as you would not use a 60A fuse typically in any case as the fuse must carry the starting load, regardless of induction choking the inrush.

But let us say that 60A is recommended.

It is not unheard of to use use a matched pair in parallel, one of them will always be more sensitive, and one will always carry slightly more than half the current.

It is not recommended as there will be a delay as they cascade, and someone will invariably swap one out for an unmatched one or even an improper value.

If it your own rail and you are testing, it is arguably acceptable. Otherwise, it is not.

HIGH VALUE sand filled fuses already have parallel elements.

https://youtu.be/0mGhhdPgXG8 (I am not this person).

Answer 5

Simple answer : DON'T DO THAT

If you put two 120V 60A breakers in serial and there something like a 61A current, the two breakers will never open at the same time. When the first breaker will start opening it will begin to reduce the current. However as side effect this can prevent the opening of the second breaker. As result that 110V breaker will receive an inductive 220V. What will happen in that state ? There two cases :

• if your very lucky : the breaker will be damaged.
• in most case : it will start fire.

As side note :

• is it a 60A nominal current or 60A max current ?
• Never use a circuit breaker based on the motor max amperage (it will not protect the motor for overloads)
• avoid to use a "normal" circuit breaker to protect a motor. it can break when the motor start.

Always use a motor circuit breaker adapted to the nominal current. And set it the the exact nominal intensity (or little less).

For info Schneider public prices in US are :

• 180.00 USD for the 6A motor circuit breaker
• 466.00 USD for the 60A motor circuit breaker

Note : theses are designed for three-phase electric power at 400V. So they are a 'little' oversized for a 220V two-phase motor. But this will be safe. However search for an adapted protection in your country.

Additional note : even if it's less risky, the same logic also happen in putting many circuits-breakers in parallel trying to sum the total nominal current. (not the maximal current) One difference : instead of preventing the other breaker from opening, the first breaker breaker will instant transfer all the load to the second breaker leaving it alone to do all the job.

Answer to @TooTea First : thanks for your comment

Just FYI, you should edit any additions into your answer (using the "edit" link under the answer) instead of posting a comment.

Merged

First, there are no "120V" circuit breakers

I live in Europe where there only 230V an 400V. And there two different circuit breakers for theses two voltages. I simply assumed is was the same in US for 110V.

once one of them trips, the circuit is interrupted and not current can flow anymore. (And no, 120V vs 240V has no effect on the ability of a breaker to extinguish the arc during a high-current trip.)

It has. If the load is inductive (like a pump) the current don't stop instantly. (that why there electrical arc on opening and it's how welding stations works). Even if the voltage across the arc only depend on it's length, the network voltage continue to push the current inside it, meaning more power to dissipate.