Timeline for Amp rating of ganged circuit-breakers
Current License: CC BY-SA 3.0
8 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Jan 14, 2016 at 10:06 | comment | added | Harper - Reinstate Monica | Big tankless heaters are built with several heating elements each of which gets its own breaker. The size of the elements is chosen by the manufacturer which decides the size of the breakers you'll need. So if you buy four 30s you may get the heater and discover you need three 40s. | |
| Jul 18, 2014 at 16:35 | comment | added | supercat | A 240V device (in the US) may look like two circuits, but they are not independent. Any time power is disconnected from one it must also be disconnected from the other. If power is disconnected from only one side, a 240V device may without warning bridge power from the powered side to the other. Someone working on the "unpowered" side at the time could be electrocuted. The only safe ways to protect a 240V device are to use a purpose-designed double-pole breaker, or else two adjacent breakers which are designed so they can be locked together to work as a single double-pole breaker. | |
| Jul 15, 2012 at 22:53 | comment | added | Bernd Jendrissek | Adding to what @shirlockhomes mentioned: circuit breakers are not like resistors that you can put in parallel to achieve a higher current carrying capacity. Instead, the one with the poorest connections will hog almost all the current, and then trip, and pass the current along to the next-poorest-connected one, where the process will repeat. Unless you're lucky and they happen to share nicely, you'll end up with just an expensive under-rated breaker. | |
| Jun 23, 2011 at 11:04 | comment | added | shirlock homes | Running multiple breaker pairs instead of a properly rated double pole breaker makes me nervous. Good advise from Shimon, get an electrician to check this one out. You are really maxing out that 200amp panel. | |
| Jun 23, 2011 at 4:48 | comment | added | Jay Bazuzi | @KeithS my neighbor just built a super-energy-efficient house but still needed 400A service because there's a tankless heater for the radiant floor, and another for the domestic hot water, and both could be on at the same time. | |
| Jun 22, 2011 at 21:34 | vote | accept | KeithS | ||
| Jun 22, 2011 at 21:34 | comment | added | KeithS | That makes all the sense in the world. So if I wanted tankless, we're probably talking about an upgrade to a 300A main breaker, or a second parallel panel (if that's legal in a SFD). I don't think I have space in the existing panel for 4 more 30A DP breakers. | |
| Jun 22, 2011 at 21:05 | history | answered | Shimon Rura | CC BY-SA 3.0 |