We just had an electric gate installed that extends across our driveway. I noticed that the installer used a 15 amp breaker switch to connect to for power (the gate is the only device on this breaker). In looking at the manual last night the installation instructions call for a 20 AMP breaker (the wording is - "Minimum: 20-amp breaker switch per gate motor needed"). In reviewing this site it looks like the size of the breaker is detemined by the size of the wire used - is this correct? Also, can I assume that if the breaker does not trip I am OK? In other words, I assume a breaker switch that is too small will just constantly trip vs. a breaker that is too large may never trip. Again he was the installation person, not an electrician. Thanks in advance!

I think you are correct, but I am not an expert, so I want to see what others will say.

I'll let the real pros chime in, but if it is 14 gauge wire that he used to install the gate, you don't have a choice, you have to use a 15 amp breaker. If he used 12 gauge, you could use a 20 amp breaker. But you would have to know for sure if the entire run of wire is 12 gauge. On the other hand, if the 15 amp break isn't blowing, then I don't think you have to worry.

No, This the above is not correct>

The size of the conductor is determined from the manufacturer's required amperage.

20 amp demand (Breaker) carries with it requirements for conductors not less than #12 AWG. And a Max 20 amp load.

Two things need to happen very quickly: (1) Contact the electrician and demand his immediate return. He did not follow the installation instructions. Even though he may have sized the load and used the metal information plates to correctley determine the load and conductor size.

(2) [/B] If he installed a 15 amp breaker and connected it to a #12 AWG conductor, only the breaker has to be changed.

However if he installed a 15 amp breaker connected to a #14 AWG conductor, both the breaker and the conductors need to be changed. A 20 amp breaker cannot be connected to any conductor lower than #12 AWG.

Go with Don's explanation. The motor determines the breaker and the breaker determines the wire size. If the installer made the mistake it is his responsiblility to fix it. Just because the breaker doesn't blow is not an OK resaon to leave it.