Sustained Is the Word That Matters
Design practice draws a line at three hours. At or beyond it, a load is considered continuous, and the conductor and the overcurrent device are both sized with a margin above the actual draw, on the grounds that heat accumulates when nothing gets a rest. That margin is the reason a charging circuit is always specified larger than the number on the charger.
The same logic applies to everything the current passes through, and that part is not in the specification. A conductor is sized off a table. A termination on that conductor is only as good as the last person who tightened it, and heat is patient.
Which is the reason the estimate starts at the panel and not at the parking space. It is the longest part of the visit, and it is where the useful information is.
It is also why two houses on the same street can want the same unit and produce two different workdays. Where the panel sits relative to where you park, what the main has been carrying on a July evening, whether the directory on the door still describes the house: none of that is visible from outside, and all of it changes the job.
San Tan Valley EV Charging Questions
1.Should the unit be plugged in or wired in?
Both are ordinary, and one detail decides it more often than people expect. A charger fed from a receptacle sits on a circuit that must carry ground-fault protection for people, usually provided by the breaker; hardwire the same unit, and that particular requirement does not apply, because it attaches to the receptacle. The equipment's own leakage detection is not a substitute, since it operates at a higher threshold than a personnel device. Past that, it comes down to whether you want the unit to be removable, and to arithmetic: a 50-amp receptacle carries 40 amps continuously, so anything set above that is hardwired, whatever you would have preferred.
2.My breaker trips partway through a charge. What is that?
Three candidates and testing tell them apart. A ground-fault breaker sitting upstream of equipment that has its own leakage detection is one, and it is the one people guess at, so rule it in or out before anything else. A connection heating at a terminal is the second, and a reset is the wrong answer to it. The third is something faulty in the circuit or the equipment. Do not sit and reset while you work out which; tell us what the pattern is.
3.Does the distance from the panel change the wire size?
Less often than the internet suggests. 40 amps flowing in 6 AWG copper drops about 4 volts over 100 feet, which, on a 240-volt supply, is under 2 percent, and the same conductor is still within 3 percent at roughly 180 feet. What changes is the conduit, the route, whether an attic crossing brings a temperature correction with it, and whether a trench or a detached building is involved.
4.What about a detached garage?
Two things travel out there, and they behave differently. A disconnecting means at the building is required either way, branch circuit or feeder. The grounding electrode is not: a single branch circuit carrying an equipment grounding conductor does not bring one, while a feeder to a panel out there does. And get the conduit size right on the day, because spare capacity in the pipe is what makes a later addition straightforward.
5.Will I need a bigger service?
Often not, and it is worth resisting the assumption. A load calculation against the output you actually want decides it, and trimming the setting is frequently enough to make an existing service work. A car sitting on a driveway from seven in the evening until seven in the morning has a great many hours to play with, which is what makes a lower setting so easy to live with.
Everything Else We Cover in San Tan Valley
Charger work often turns into panel work. Our other services here:
What San Tan Valley Customers Say
Our Google listing is not curated, and there is no testimonials page. The live feed below is the whole record, good and bad, which is the only version worth reading.