circuit breaker question 1

[jumacao]

A device says it need and electrical utility and a circuit breaker of 10 A. Now, it have a circuit breaker of 20 A. Is 20 A OK or it is wrong?

What is the function of the circuit breaker ?

 

[MiketheEngineer]

It or the wires going to it might burn up... If you can live with that - OK otherwise use the 10A as specified.

 

[LionelHutz]

What is the function of the circuit breaker ?

You should not be making these decisions if you need a simple question like this answered.

 

[jumacao]

Thanks for you lack of help Lionel. I am verifying the installation. The breaker was a discrepancied. Some people in this phramaceutical industry usually did not changes the site breaker to match the vendor requirements. SOme of them argue that breaker is for the wiring that the machine should not care about what breaker the utility had. So, I am asking the question to see if the argument have any base.

 

[jraef]

We must be on guard against people attempting to use us as a no-cost alternative to hiring an engineer, and the nature of your question made it appear as such. Please do not misjudge the actions of people who's primary concern is the safety of others. Your more detailed explanation was helpful to understand the nature of your query. Perhapse had you provided that at the outset we could have avoided the unpleasantries.

That said, the comment that the breaker is there to protect the wires is the slightly more correct of the two, but it just is not that simple. Typically, a machine or device will have been designed with a specific type of circuit protection requirement, and to attempt to interpret someone else's engineering decisions is a minefield of potential dangers. We cannot know, nor can you, nor can anyone else who thinks they know just from a brief description. Only the engineer who said "use a 10A circuit breaker" can be expected to know if another value is possible. To guess is to risk fire and harm. So bottom line, the only safe response is, do not interpret of change what was said unless you are willing to accept PERSONAL responsibility for all possible outcomes.

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[burnt2x]

@jraef, Amen, brother. If only everything is laid up front, any Simon or Peter can answer correctly.

@jumacao, lay down your predicate. Size of wire deriving power from breaker, loads being supplied by those lines, etc. . , etc. . etc.
Then we can talk sensibly.

 

[LionelHutz]

The device is specified to use a 10A breaker so use a 10A breaker. The "people" arguing for the 20A breaker are likely doing so because they're too lazy to go back and fix their problem.

 

[automatic2]

it would be wrong. The specification is likely based on a UL or similar rating, where they have identified a need for overcurrent protection of that level. Circumventing this only increases your exposure to equipment damage or personal safety concerns.

 

[waross]

Check the fine print for the word "minimum". In the NEMA world A/C equipment often has an information for the minimum circuit ampacity.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[jumacao]

I am a professional engineer. My believe is to always used the correct specified breakers. Because another engineer was arguing against that because he says that machine had its ones protection. Then, I decided to asked the question to looks for opinions.

 

[automatic2]

you need to specify your query a bit more, particularly if your an engineer. If the equipment does in fact have it's own protection, there would be no reason that you couldn't supply it with a higher rated circuit. In fact you would to provide cordination of trips.

So tell us,are your querying the device itself (as you appear to be), or the branch circuit that supplies the device.

 

[LionelHutz]

So, does this machine have it's own protection?

Arguing that the breaker can be 20A instead of 10A because the machine has it's own protection is not a valid arguement if the machine in fact does not have it's own protection.

I would expect the machine does not have it's own protection since the machine documents specified a 10A breaker.

You still need to use a 10A breaker given the information you have provided. You haven't given any info that would indicate otherwise.