The Blue View - Calculating Electrical Loads

It is usually quite simple to calculate the electrical load on a circuit. If there is only one electrical device connected to the circuit, the load is simply the amount of current the device consumes when it is running. If a circuit only powers an electric bilge pump, and the pump draws 8 amps, then this is the load. The wiring and fuse or breaker must be adequate to handle 8 amps.

If there are several devices connected to the circuit and all are often running simultaneously, then the total load can be calculated by adding up the current requirements of each device. For example, if we have an autopilot that requires 6 amps, a GPS that draws 2 amps, and a chartplotter that draws 3 amps, then the total load on the circuit would be 11 amps.

But what if we have a number of devices connected to a circuit, some of which may be on all the time and some of which are on only part of the time? Do we tally up the loads for every device and design the circuit to handle this worst case load? Do we take the average load? Maybe the average load plus a fudge factor? If we guess wrong in one direction, we will be popping breakers or blowing fuses on a regular basis. If we design the circuit for the worst case scenario, we will be spending a lot more on wiring and breakers than we probably need to.

Fortunately, the National Fire Protection Association (NFPA) as well as the American Boat and Yacht Council (ABYC) provide some guidance. The ABYC provides a worksheet developed for boats, and it is quite helpful in determining the likely total load on a circuit that has multiple devices. I've modified it slightly and show it below.

The two columns on the left side are for devices connected to the circuit that are on either continuously or for long periods of time. There are several blank lines provided, so if your boat has other devices on the circuit, add them in 'Column A'. Next enter the current required for each device in the 'Amps' column, and add these all up and enter the total in the cell labeled 'Total of Column A'.

The columns on the right are for devices that are only on occasionally. Again, add any additional devices in 'Column B' and then enter the current required for each device in the 'Amps' column. Add these all up and enter this total in the cell labeled 'Total of Column B'. Now multiply this by 0.1 and enter it in the following cell, '10% of Total of Column B (1)'.

Scan the 'Amps' column on the right side and find the largest single load. Enter this in the cell labeled 'Largest Single Item of Column B (2)'. (Not too difficult to follow so far, eh?). Enter the larger of the two values, either (1) or (2), in the applicable cell on the left side, and add it to the 'Total of Column A' cell. The resulting sum is the total load likely to be seen at any given time.

I find the process to be fairly straightforward, and much easier than, say, filling out a 1040 Tax Form.

Next week, I'll talk about circuit breakers and fuses. Stay tuned.

Want a date? China Ranch Date Farm

No, it's not a social media dating site. The China Ranch Date Farm actually grows, harvests and sells dates. We learned about the farm during our recent visit to the Springs Preserve and decided it would make a good day trip from Las Vegas. Located in Tecopa, California, it's a 90-mile drive along the Old Spanish Trail Highway, the old trade route between Santa Fe, NM and Los Angeles, CA. Once out of Las Vegas, we traveled through the aptly named Red Rock Canyon and over the Mountain Springs Summit (alt. 5502') and felt our ears pop. The mountaintops were snow-covered and picturesque. Snow is always more picturesque at a distance and when it doesn't require shoveling.

As we ventured further into the Mojave Desert, the landscape changed significantly. Joshua trees, sage, scrub and cacti took over the land. Houses and towns are few and far between in this area. We watched the temperature plummet from near 70F in the city to the mid-40s in the high desert. We crossed the state line into California quite unceremoniously.

We arrived at the road to China Ranch Date Farm and it seemed an unlikely place for a date palm orchard. The last two miles was a winding, steep, gravel road through surreal sandstone cliffs. Erosion has created windows on the cliff tops.

Old gypsum mine shaft entrances were plentiful and fenced off to keep curious visitors at bay.

The date palms came into sight quite unexpectedly … a huge orchard of them. Dates hung invitingly as we wandered around and between the luxuriant palms. Bird song was everywhere. We observed two coyotes on the prowl, but they disappeared once they spied us.

So … a little date trivia. The date palm, native to northern Africa and the Middle East, first came to the US in the 1890s. They thrived in the deserts of Nevada, California and Arizona and currently, “the USA date industry produces more than 60 million pounds of fruit annually. Iraq is the world's largest producer of dates.”

Now, what about the name: China Ranch Date Farm? Well, it appears that a Chinese borax mine worker (Ah Foo ??) came to the area some time in the mid-late 1800s. He developed the water source, planted fruits and veggies and raised cattle to supply the local miners. The locals predictably called it Chinaman's Ranch. Along came a guy named Morrison c. 1900 who ran off the Chinese fellow at gunpoint and claimed the developed land as his own. The land has had many owners since and has been used for several different purposes. In 1970, the Brown-Sorrells family purchased the land and it remains in the families today.

After a stroll through the orchard, we visited the gift shop from which enticing smells were emanating.

Freshly baked date bread, date muffins and cookies were on offer and several varieties of dates were available for sampling. Karen tried several and reported them all delicious. It was, however, the rather unusual date milkshake that finally lured all three of us in. Different and delicious, but filling and very, very sweet.

We sat outside the gift shop at a picnic table on a small outdoor patio. Anna's hummingbirds hovered above us as we sipped our milkshakes and appreciated the warm sunshine.

The surrounding area was definitely photo-worthy.

There are several hiking paths and trails along the Amargosa River, but we were not prepared for a long hike, so instead we visited the ranch's “Modest Museum”. Actually, “modest” was probably too complimentary of the tiny 2-room ramshackle cabin which contained more cobwebs and spiders than photos or memorabilia. The “tour” didn't take long, but did provide a laugh or two.

All in all, we found the day trip to China Ranch Date Farm to be a pleasant diversion. Next time, we'll be prepared for a little hiking ... to walk off the date milkshakes.

Valentine's Day 2017

It's Valentine's Day tomorrow and, of course, we plan to celebrate in style. Ethel M's, a local upscale chocolatier, has a botanical cactus garden that is pretty spectacular to tour during the day. Around Valentine's Day each year, they dress it up with a half million sparkling colored lights and open it to the public for night time viewing. We visited last year and decided it was worth another visit this year.

The night was mild and mellow. The full “Snow Moon” was obscured by the clouds. There was a sizable crowd at the gardens, but the number was not overwhelming. We strolled hand in hand along a maze of cactus-lined paths that twinkled and glowed in the darkness. Reds, pinks and purples dominated the “Lights of Love” (corny, huh?) display.

The use of backlighting and shadow made for interesting viewing. A new technology (at least to us) known as meteor shower lighting accounted for a fireworks effect. Dazzling brightly colored reflections danced on the walkways … candy for the senses.

We've made plans for an intimate, romantic dinner at Casa di Amore, a noted Italian restaurant in town that touts “Vegas the way it used to be”. Since we don't know what “Vegas used to be”, it'll all be new to us … but the reviews we read are great. We don't dine out all that often, so we're looking forward to this special occasion. How could we go wrong on Valentine's Day eating at Casa di Amore (House of Love)?

To look back at how we celebrated in years past, take a look at Valentine's Day in Australia in 2014 and Lesotho in 2015.

Hoping you're loved on Valentine's Day!