Summary: All about fuses and circuit breakers and how they have evolved over the years and are used to protect your home electrical system.
By: Dave Rongey
Fuses and Circuit Breakers for the Home Electrical System
Fuses have been around for a long time, and there are still electrical systems today that are protected using certain types of fuses.
Modern house wiring methods today do not include older fuses, in fact rewiring older homes and replacing the old fuse box is always recommended. Just like the older screw based fuses, electrical circuit breakers conveniently protect our home electrical wiring circuits and rarely wear out unlike the one time fuses that needed to be replaced when the circuit became overloaded.
The History of Fuses and Circuit Breakers
How fuses and circuit breakers can be helpful for your home.
The Edison Screw Based Fuse
A typical older home had an electrical panel with a few circuits that were protected by screw based fuses. Although this type of protection was reliable, the circuit integrity was often compromised by easily installing an oversized fuse which often lead to overheated circuit wiring and caused many house fires.
Screw Based Circuit Breakers
One improvement in screw based fuses was this push button circuit breaker. This push button circuit breaker style fuse eliminated the need of having to replace a burnt out fuse. Other improvements were fuses that had a mechanical time delay that would prevent the fuse from blowing when the circuit had a sudden surge of electrical current due to larger devices such as a refrigerator.
Electric Panel with Cartridge Fuses and Screw Base Fuses
The home electrical system began to see larger circuits which required more protection which was provided by cartridge fuses. These fuses have been used as the main electrical service protection being enclosed in a pull-out assembly that also served as a service or circuit disconnect. It was common to see two of these cartridge fuse disconnects, one for the main electrical service typically 60 amps 240 volts, and one 30 amp 240 volt circuit for a large circuit such as a well pump or a circuit to a barn or out building.
Cartridge Fuses for Large Electrical Circuits
Cartridge fuses are still used today for larger electrical circuits for equipment such as an air conditioner. Typically cartridge fuses are found on 240 volt circuits that require a disconnect to be close to the equipment enabling the power to be turned off while the equipment is being serviced.
Modern Day Circuit Breakers
For several years, the modern switch style circuit breaker has been used to protect all the electrical circuits for a modern home. These circuit breakers come in a wide range of amperage ratings and are used for 120 volt and 240 volt circuits. These circuits are know as single pole, double pole and three pole circuits which are found in commercial and industrial electrical services.
More about Fuses and Circuit Breakers
Question:
When upgrading a service panel from fuses to circuit breakers in residential housing are AFCI breakers required or just on new construction?
Answer:
The inspectors in my county do not require me to do any other work when I get a permit to only upgrade the panel. There may be requirements in other areas which may address certain issues such as smoke detectors, gfci's or possibly afci's.Your best bet is to call the Building department in the Randolph area and ask them.
Its always a great idea to speak to the inspector who is assigned to your permit - they are usually very open to your questions and will usually help you out very nicely. A great attitude towards them will typically produce a great attitude back to you.When remodel work is taking place inside the home, then the building department will require those affected areas to be brought up to code.If you are planning to do additional work inside the home later on, make sure to think ahead and pre-wire for any circuits which will be needed. These can always be placed in the attic or crawl space in a junction box where they can be capped off and identified for future , the same back at the panel.
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Questions about Fuses and Circuit Breakers
Rod in Minnesota asks: Can a Electric Fuse Socket Become Defective?
Our daughter has home built in the 60s with fused service panel. One fuse has started blowing ; when a new fuse is put in, it will not blow right away, it can go for hours sometimes without blowing. It is a 20- amp fuse circuit. On the circuit is a microwave and several regular outlets. The microwave has not been in use when the fuse blows. There is nothing excessive on the circuit and just normal use. Nothing out of the ordinary is being used when the fuse blows. I have checked that there are no foreign objects in any of the outlets. I have read that the fuse SOCKET can sometimes be defective, after decades of use. Do you think that is a possibility? The fuse socket contact looks a little pitted to me but I don’t know if enough to be a problem. I cleaned it with a toothbrush and electrical cleaner (sparingly) and let it dry well before reinserting fuse. It didn’t seem to help, the fuse still blew after a few hours. The fuse blows randomly (no set time or period of time). The panel is dry, I see no evidence of water intrusion. The fuse is Bussman SL 20 amp.
Dave’s Reply: Time to Upgrade an Electrical Service Panel
An older fuse panel can produce several problems, especially as the electrical circuit load in the home increases. Over time the electrical contacts of the fuse box components can break down and wear out, and this can cause over heating and even blown fuses. Even though repairing the parts may help for a while, the time to upgrade the electrical service panel, and the home electrical circuits will always be the best solution.
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fuses and circuit breakers - 1733
Installing Electric Circuits
Electrical Project Skill Level:
Intermediate to Advanced - Best performed by a Licensed Electrical Contractor.
Electrical Tools Required:
Basic Electricians Pouch Hand Tools and a Voltage Tester.
Estimated Time:
Depends on personal level experience, ability to work with tools, install electrical circuit wiring, and the available access to the project area. Electrical Safety:
Identify the panel circuit, turn it OFF and Tag it with a Note before working with the wiring. Working in an electric panel is dangerous due to arc flash hazards and the possibility of electric shock.
Electrical Wiring Parts and Materials:
Electrical parts and materials for circuit wiring projects should be approved for the specific project and compliant with local and national electrical codes.
Electrical Codes and Inspections:
Installing additional electrical circuit wiring should be done according to local and national electrical codes with a permit and be inspected.
This is a testing tool that is a Non-contact tester that I use to easily Detect Voltage in Cables, Cords, Circuit Breakers, Lighting Fixtures, Switches, Outlets and Wires. Simply insert the end of the tester into an outlet, lamp socket, or hold the end of the tester against the wire you wish to test. Very handy and easy to use.
This is great to troubleshoot a problem with outlet circuit wiring, is also used by most inspectors to test for power and check the polarity of circuit wiring.
It detects probable improper wiring conditions in standard 110-125 VAC outlets
Provides 6 probable wiring conditions that are quick and easy to read for ultimate efficiency
Lights indicate if wiring is correct and indicator light chart is included
Tests standard 3-wire outlets UL Listed Light indicates if wiring is incorrect, Very handy and easy to use.
A wire stripping tool used to safely strip electrical wires.
This handy tool has multiple uses:
The wire gauges are shown on the side of the tool so you know which slot to use for stripping insulation.
The end of the tool can be used to grip and bend wire which is handy for attaching wire onto the screw terminals of switches and outlets.
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