Letter Re: Don't Forget the Fuses

Thursday, Aug 15, 2013

For  those of you planning on bugging out with a knife and a backpack when the SHTF, read no further because nothing in this article will be of value to you. For those of us who, for one reason or another, have to plan on bugging in, this might serve as a reminder to stock some cheap but necessary items that you may not have considered. Judging by the number of survival threads and articles that I have read, a number of us plan on maintaining, if possible, some sort of energy source should EMP, flood, hurricane, terrorist act or other event disrupt our electric service. At times like this, we can expect blackouts, rolling blackouts, brownouts, surges, peaks or other electrical gremlins to occur. All of these things place stress on electrical and electronic devices and the components designed to protect them; fuses. In addition to blowing out, fuses wear out. This is most common in devices that draw large amounts of power and are switched on and off frequently such as home HVAC units.  Heavy current flow through a fuse generates heat and the fuse link expands and contracts with the temperature change until metal fatigue finally takes its toll. Take inventory of all of the electronic and electrical devices around your bug in location and you will be surprised at the variety of fuses necessary to keep things running. Yes, I know, you can often bypass fuses to keep something running in an emergency but you also bypass the item designed to keep the device from burning out or malfunctioning, possibly when you need it most. Fuses are low cost items that are readily available during normal  times but that is not what we are talking about, is it?

Start by examining the service entry box at your house. If it is an older house, it may still be wired with screw-in plug type fuses. Modern electrical devices cumulatively draw more current then these systems were designed to handle and you are probably already accustomed to occasionally replacing some of these fuses. It might be wise to accumulate a large supply of those fuses in advance in the event a trip to the local hardware store is not wise in the future. If your house has a panel of circuit breakers, examine it closely to see if all of these breakers are rated at 25 amps or below and, if they are, the panel will also contain a pair of large cartridge type fuses, often concealed behind a large Bakelite handle which also serves as a disconnect device. A spare pair of these fuses is a cheap investment. Remember, brownouts and surges can stress components to a level above normal.

Start closely examining the instruction books and manuals for the various types of electrical and electronic equipment that you own. If you are so talented, open up the devices and examine them carefully for fuses which are often placed somewhere in the device close to the power input source. These fuse devices are not generally meant to be user serviced but, in an emergency, might allow you to retain the use of a critical device. Some of these may not appear to be the normal type of fuse that you are accustomed to seeing but may quickly disable the device in the event of a power surge. Enlist the help of a knowledgeable friend if you are not comfortable doing this. The circuit boards will often be marked with numbers identifying the parts and fuses are often designated with numbers such as "F101" etc. I recently opened up a 2000 watt power inverter to find that it contained eight 250 watt inverter modules, each with its own 40 amp fuse! If this inverter were to be overloaded or subjected to an extreme power surge, it would be possible that these fuses could all blow out in sequence as the remaining modules each attempted to assume the load vacated by the first module to blow out. Don't forget charge controllers and  the inline fuses in the connecting wires of 12 volt radios, scanners and CB sets. Also, closely examine the cigarette lighter plug  which allows you to run some devices off your vehicle's electrical system for a cartridge type fuse behind the tip of the plug. The very popular Maha MHC9000 charger often used with Eneloop batteries has such a fuse in its 12 volt cord as does the charger for my 2 meter ham radio and the vehicle charger for my Craftsman power tool batteries. I have also seen cigarette lighter plugs which use miniature blade type fuses inserted into the side of the plug.

By the way, if one of your power tool batteries suddenly goes "dead", particularly after you have stalled or overloaded the tool, open the battery up. Inside, you may find a small strip of metal that is used to interconnect the individual cells in the battery and see that there is a melted gap in one part of the metal. That is a fuse! You can make an emergency repair and continue to reuse the battery by carefully soldering a small piece of copper wire across the gap. Try to avoid using too much heat while doing this and use a good grade of rosin core solder. Scraping the metal for a clean surface in advance often helps the solder to adhere to the metal.

Last and certainly not least, check your owner's manuals for a complete listing of the fuses used in your vehicles. Many modern vehicles contain more circuits than your house and use a wide variety of fuses. A large kit or selection of those fuses would be a good investment. Harbor Freight sells assortments of the common sizes of blade type fuses at reasonable prices. If you have a RV equipped for bugging out, don't rely on the owner's manual to tell you about every fuse hidden in the vehicle. Trace the wiring for everything that connects to either the incoming AC power, the onboard generator if so equipped, or the "house" batteries for inline fuses as well as any fuses installed in fuse panels or blocks. Some RV refrigerators have fuses hidden inside them. Again, a knowledgeable friend may be very helpful. The Ford chassis used as the basis for my class B motor home has a master fuse block located under the hood and a second fuse block beneath the dash and they each use different sized fuses. The coach itself has fuses in the inverter/charger unit and large fuse links in the battery bay. Again, trace the wiring.

Fuses may seem like small, unimportant items but remember, "for want of a nail, the shoe was lost………..". You can't have too many fuses as some problems may be reoccurring until the fault is located. Be safe, be prepared.  - G.L.D.   

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