Inside A Circuit Breaker With MikesElectricStuff | 220v Contactor Relay

This doesn’t make any sense, why not use an extension cord with the 220 already in the house? A 6 or 8 gauge cord for 75 feet should be perfectly fine.

Step 2:  To determine which MOV disc size to use, first identify the MOV series that minimally meet the 1000-A surge requirement. Inspecting the table above suggests a 20-mm MOV with a 31-V dc maximum continuous voltage rating (part number V20E25P) as a possible solution to meet the requirements.

Anyone that knows me really well, especially family members, is surprised/amazed that I’ve managed to be over 50 and still more or less bilaterally symmetrical, without too many visible scars.

Aluminum wire has a lower ampacity than the same gauge copper wire, meaning aluminum must be larger to accomplish the same ampacity job as copper wire. The rule-of-thumb sizes rely on the lowest allowable temperature rating of the wire; in some cases, the circuit may have a higher ampacity if the insulation on the wire and the connection endpoints are all rated at 75°C (167°F) or 90°C (194°F).

That depends on the country. I live in Europe, and people here are allowed to do basic repairs and modification with mains voltage, like adding extra outlets. All the materials such as PVC conduits, wires, outlets, lights, switches and dimmers are readily available in the hardware store. It is however not allowed to mess with anything before the meter or fuses. Some equipment like electric stoves don’t come with power cords. Instead, you open up some compartment, and attach the wires on some screw terminals.

Step 1:  To find the voltage rating of the MOV, allow for 20% headroom to account for voltage swell and power-supply tolerances: 24 V dc × 1.2 = 28.8 V dc. Given that no varistors have a voltage rating of exactly 28.8 V, check the datasheets for specifications for 31-V dc MOVs.

I think the only conceivable danger to using relays would be that they could weld themselves shut. But in this case, the relay contacts are rated for 30A and I’d not be likely to exceed even half that. The only other failure modes of relays are safe (the relay failing to close, for example).

We, uh, we don’t have sauna heaters down here. We have air conditioners In semi-related news, it was forecast to be 40C today…

I liked your article. It had a lot of good pointers for others. It may be a good idea to add a red indicator between neutral and ground for the two incoming 120v lines. That way, if the hot and neutral are reversed, the light will come on.

The Sony A33 uses the image sensor itself when metering, and considers the overall image as 1,200 separate zones in performing metering calculations. Metering modes include Multi-segment, Center-weighted, and Spot, and the metering system can function from -2 EV to +17 EV (at ISO 100 equivalent with an F1.4 lens). An autoexposure lock button is provided, allowing metering to be locked from a specific portion of the subject, then the overall image reframed as desired. +/-2.0 EV of exposure compensation is available, in 1/3 EV steps. The A33 also offers a three-frame exposure bracketing function, which allows a step size of either 1/3 or 2/3 EV between subsequent frames. Shutter speeds from 1/4,000 to 30 seconds are available, as well as a bulb position that holds the shutter open for as long as the shutter release is pressed. Flash X-sync is at 1/160 second. White balance options include auto, six presets (Daylight, Shade, Cloudy, Incandescent, Fluorescent, and Flash), plus both custom and direct color temperature (2,500 to 9,900K) options. The six presets allow +/- 3 step adjustment, and there’s also a color filter setting that provides +/-9 steps of magenta / green compensation.

Just took a few seconds? the speed of light must be a bit slower in whatever dimension you’re living in.

Flash. The Sony A33 includes an auto-popup flash strobe with a guide number of 10 meters at ISO 100, as well as a proprietary flash hot shoe. The built-in flash has 18mm coverage, and a recycle time of four seconds. Flash modes include Auto, Auto w/ Red-eye reduction, Fill, Fill w/ Red-eye Reduction, Slow-sync, and Rear-sync. Flash metering modes include ADI and pre-flash TTL. +/-2 EV of flash exposure compensation is available, in 1/3 EV steps, and flash exposures can also be bracketed, with three frames varying by 1/3 or 2/3 EV. External strobes including the HVL-F36AM, HVL-F42AM, HVL-F56AM, and HVL-F58AM support high-speed sync and wireless shooting.