Are Siemens QP and QT Breakers Interchangeable? (Explained)

are siemens qp and qt breakers compatible

People use interchangeable breakers for various reasons. For instance, if you can’t find your brand of choice, it makes more sense to use an alternative from a different brand. Siemens QP and QT breakers are fascinating because they technically originate from the same brand.

Are Siemens QP and QT breakers Interchangeable?

QP breakers are 1-inch per pole branch breakers, while QT combines a pair of 1/2-inch breaker poles. They have similar physical dimensions. They could fit in the same space. However, I don’t suggest interchanging them because if you damage the breaker or panel while trying to interchange them, it may void your warranty. Additionally, interchanging breakers can lead to arcing and fires, especially if the two breakers in question are loose-fitting.

If you’re determined to experiment with this practice despite the consequences, make sure the breakers have the same load capacity. You should also consult a professional, just to be on the safe side.

A contractor will look at the size, shape, rating, and engineering of QT and QP breakers to determine their compatibility.

Consider the following factors:

1). Don’t Interchange Breakers From Different Brand

Usually, you can’t interchange breakers from different brands. It isn’t safe. You don’t understand the engineering that went into the development of a particular breaker. As such, you cannot predict the consequences of inserting a breaker into a panel from a different brand.

However, before you celebrate the fact that QT and QP breakers exist under the same umbrella, you should also realize that breakers under the same brand are not automatically interchangeable.

For instance, if a breaker is part of a particular product range or series, you are better off interchanging that breaker with other products within the same series.

2). The NEC Opposes This Practice.

Even though two breakers from different brands can fit into one another’s panels, that sort of interchangeability has not been tested. In other words, no one has bothered to find out what happens when you use a QT breaker in place of its QP counterpart or vice versa.

Without proper testing, this practice is too risky. If you’re determined to adhere to the NEC’s rulings, you won’t interchange QP with QT.

3). Manufacturers Hate Interchangeability

Most people don’t rely on manufacturers to show them compatible breakers because manufacturers hate interchangeability. They always prohibit the practice because it affects their profits.

They don’t want to give consumers an excuse to buy breakers from their rivals. However, some companies are different. Their panels will include a list of every compatible breaker. You can also check each company’s online platform for clarification.

Siemens doesn’t expect consumers to interchange QT and QP breakers. Their manuals and documents do not encourage this practice.

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4). Check The UL Charts

I want you to check the UL charts. Underwriter’s Laboratory is a third-party entity that tests items like breakers, verifying their quality and viability. Underwriter’s Laboratories will test some brands of breakers to determine whether or not they can work in panels from different brands.

They will list all the breakers that can work in the panel you have chosen. Even though the manufacturer discourages the practice, you are free to use any breaker UL has recommended, regardless of the difference in the brand.

UL wouldn’t recommend the breakers on its list unless it were sure that consumers could interchange them safely without suffering any drastic consequences. Although, they have warned consumers against performing installations without the assistance of a qualified professional.

What does all this mean? At the moment, interchanging QP and QT breakers sounds like a bad idea.

Difference Between Siemens QP and QT Breakers

QP and QT breakers are not the same. QP breakers are Siemens’ Q series of products. These breakers snap into panels, which is appealing because you can install them with great ease. QP is popular. People appreciate their innovative technology and sturdy build.

They work with Type Q panels from various brands, including Arrow Hart, Westinghouse, and Murray.

QT breakers are just as popular as QP. In fact, they are more popular in some circles. Instead of Type Q panels, QT breakers appear in panels that accommodate Type QC and QD breakers. Like QP, you can use QT breakers in Arrow Hart, Westinghouse, and Murray panels.

In truth, they can fit most panels because installation is so easy. However, you are better off restricting these devices to the panels the manufacturer has listed.

No one would blame you for confusing QT with QP. After all, QT is a version of QP. If you want a duplex, triplex, or quadplex breaker that shares QP’s attributes, QT is your answer. You get two half-inch breakers in a one-inch space. This space-saving feature makes QT superior to QP in the eyes of many people.

You can’t go wrong with either option. Additionally, you have no reason to interchange them. Both breakers are easily accessible. If you prefer a different brand, use one of the options Siemens has emphasized (Westinghouse, Arrow Hart, Murray, etc.). There is no reason to interchange QT and QP.

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