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Modification of Old Electrical Work
Electrical and building codes have changed over time and new methods proscribed for safety. Converting the old to the new leads to lots of questions.
500 Questions
What is the point of grounding your house?
Asked by Wiki User
All electrical distribution systems require a system earth ground for personnel safety. The ground for your home electrical system is likely a grounding rod, a 10 ft. copper clad steel rod driven into the ground and then bonded with a brass clamp and large bare ground wire to your panel. This provides a path to ground to dissipate errant current which can occur due to a circuit which "shorts out." Better it goes to ground than into you!
How do you tell a positive wire from negative wire?
Asked by Wiki User
A Discussion has been started about this Question and Answer.
To add your own comments please click on the 'View Discussion' button below these Answers.
=== === <><><> If you needed to ask this question here, one of the most important things you must learn is how to use an electrician's multi-meter correctly and safely. This is one of those questions... If you know this little, you shouldn't be planning to do what you are planning... No disrespect intended, but this is SO basic that it suggests you have not studied the subject at all! There are many good reference books and course books to study from. === === <><><> This question is not as easy to answer as you may at first think. It all depends if you really know what you mean when you say "a positive wire" and "a negative wire". Are you asking about an AAA cell or are you asking about mains voltage alternating current? So take the advice given above and learn how to use a multimeter - safely - to measure voltages and currents used by electrical items or systems. Some of them use direct current power supplies, such as dry cells or batteries; other things use alternating current power supplies such as 120 Volt or 240 Volt power mains. You really need to know about both types because none of them are safe to play with, not even the simplest dry cell or battery. If you want to ask this type of question again please be sure to say: * exactly what type of electrical item or system it is that you want to know about
and
* where those wires are on (or in) the item or system that you are curious to know about which wires are positive or negative. Then someone may be able to help you by giving you a more specific answer.
IF YOU ARE NOT ALREADY SURE YOU CAN DO THIS JOB
SAFELY AND COMPETENTLY
REFER THIS WORK TO QUALIFIED PROFESSIONALS.
If you do this work yourself, always turn off the power
at the breaker box/fuse panel BEFORE you attempt to do any work AND
always use an electrician's test meter having metal-tipped probes
(not a simple proximity voltage indicator)
to insure the circuit is, in fact, de-energized.
Are t8 bulbs being discontinued?
Asked by Wiki User
No they are controlled by an electronic ballast. It's t12 and magnetic ballasts that are phased out
Is L1 white or black wire?
Asked by Wiki User
In most circumstances and electrical schematics L1 is black and L2 is white. L1 is usually the "hot" wire and L2 is the "neutral".
Is it necessary to ground at all metal junction boxes when using metal conduit or cable?
Asked by Wiki User
In a completely metallic conduit system it is not necessary to ground each junction box as long as the metallic system has the grounding capacity rating larger than that of the over current device protecting the circuit. The code book states what size conduits are rated at, for grounding amperages.
Is the black wire always the common wire?
Asked by Wiki User
In the U.S., the white wire is common. This connects to the wide slot of an outlet. You should verify this, either with an outlet tester or voltmeter, since you don't know who may have been working on the wiring before. If you don't have experience working with house wiring, I would recommend getting a do-it-yourself book to be safe, and make sure your work meets code.
Does the code permit the ampacity of switch legs to be less than the ampere rating of the branch circuit?
Asked by Wiki User
No, and here's why: the rating of the branch, determined by the overcurrent protection, is designed for the ampacity of the branch conductors so that they breaker trips before the conductors heat up enough to start a fire. If you put in smaller wires on the same branch, they will get MUCH hotter before the circuit breaker trips, if it ever does.
For example, a 20A branch, protecting 12AWG wiring; add some 14 AWG rated for 15A. Something faults the switched leg at 18A; enough to burn out the wiring but not enough to trip the breaker. House burns down, insurance doesn't pay because of "faulty wiring" installed negligently by a person without proper training and credentials.
Can I install 200 amp panel using 200 amp meter?
Asked by Wiki User
yes The meter rating is the maximum, if you use it on a smaller service that is OK from a code point of view. However, the local utility company may also have special rules about which meters pans can be used on which type installations. You may need to check with them
How do you wire a motion security light from the box to the light?
Asked by Wiki User
You wire a security light like any other light. The sensor is generally part of the light and provides an "auxiliary" switch to detect movement and switch on the light, usually only after dark.
The regular light switch for the security light should be left "on" at all times and labeled or enclosed to prevent being accidentally turned off. The sensor will not work, and the light will not go on, if the regular light switch it not on.
Many modern units allow you to "lock" the motion sensor on by using the regular light switch to turn off the circuit and quickly turn it on again. This makes the light stay on until morning, when the photocell will turn it off and reset the lock, even without any motion detected.
How many watts will a 20 amp two pole breaker handle?
Asked by Wiki User
Answer for USA, Canada and countries running a 60 Hz power supply service. Watts= voltage X amps At 120 volt total watts would be 2400 at 20 amps. The electrical code states that circuit conductors that are fed by this breaker on a continuous load can only be loaded to 80%. #12 wire rated at 20 amps, derated to 16 amps continuous = 16 x 120 = 1920 watts, #10 wire rated at 30 amps derated to 24 amps continuous = 24 x 120 = 2880 watts. On load calculations this derate should be taken into consideration. To maintain the required wattage needed for the load the wire size and/or the next size breaker may be needed.
What is transformer polarity?
Asked by Wiki User
'Polarity' describes the sense (direction) in which the voltage (not current!) induced into secondary winding is acting, relative to the sense in which the voltage applied to the primary winding is acting.
In North America, a transformer's high-voltage winding terminals are identified by the letter H, and the low-voltage winding terminals by the letter X. In the case of a two-winding transformer, the pair of high-voltage terminals are marked H1 - H2, and the pair of low-voltage terminals are marked X1 - X2.
When the potential of HV terminal H1 'goes positive' (i.e. during the first half-cycle of AC), if LV terminal X1 also goes positive at the same time, then the transformer is an 'additive polarity' transformer. On the other hand, if terminal X2 goes positive at the same time as H1, then the transformer is a 'subtractive polarity' transformer.
Knowing the polarity of a transformer is very important if you intend to operate transformers in parallel with each other (there are other factors, too, of course), in the same way as it is important to know the polarity of a battery before you can connect it in parallel with another battery.
On a light switch what color is normally the ground wire?
Asked by Wiki User
That depends on the country, and the type of circuit. In the US, on 120 volt circuits, the ground wire is usually a bare, uncolored wire or a green wire that is attached to a green terminal screw. DC circuits have a red positive, black negative, no designated ground. In other places, there are other voltages, other codes, and colors will vary.
How do you remove a cover on a fluorescent fixture?
Asked by Wiki User
To remove the cover of most florescent light fixtures, simply locate and unscrew the screws holding the frame in place. Once the frame is removed, the cover will either lift or slide off with ease.
What size wire do you need to run a 240V plug for a dryer?
Asked by Wiki User
the size of the wire that you need to run depends on the the amperage of the device/appliance you'll be hooking up to that line. Use #12 wire for 20 amp, #10 for 30 amp, #8 wire for 40 amps and #6 for 50 amps. Hope that helps.
Why does your GFCI trip when you plug in the refrigerator?
Asked by Wiki User
A GFCI trips whenever it senses a grounding problem. Not grounding the outside surface of radios, fans, fridges, metal lamps and hand tools can put 120 volts on the device where you can touch it and possibly be killed.
The GFCI trips so you will not be killed. Best to have an electrician check out your fridge. If it is OK, then the GFCI may be at fault.
Is the black wire the hot one or the black wire with a white line down it?
Asked by Wiki User
It all depends on where the wire is installed!
In Direct Current systems such as in a car or truck a black wire may be negative but that should not be assumed. Always check first, using a voltmeter.
In Alternating Current mains wiring systems it may be:
- "Hot" in USA or Canada, or other countries which use the same 60 Hz system
- "Neutral" in the UK in mains wiring done before 2005. (After 2005 new mains wiring has to use Blue for Neutral, as for the rest of the European Union.)
SAFELY AND COMPETENTLY
REFER THIS WORK TO QUALIFIED PROFESSIONALS.
If you do any such work yourself,
always turn off the power at the breaker box/fuse panel
BEFORE you attempt to do any work AND
always use a meter or voltage indicator
to insure the circuit is, in fact, de-energized.
Can you convert a hard wired fixture into a plug in type?
Asked by Wiki User
If you are taking the fixture down yourself, please be careful. BEFORE ANYTHING ELSE, MAKE SURE THE BREAKER IS TRIPPED ON THE LINE YOU ARE WORKING ON. DO NOT RELY ON A SWITCH BEING IN THE "OFF" POSITION. IN OLD CONSTRUCTION, FIXTURES WERE OFTEN WIRED HOT WITH ONLY A SWITCH LOOP TO THE SWITCH. Ok, you have to start by "reverse engineering" - you have to figure out how the fixture was attached to the wall or ceiling. Once you've got it off the wall or ceiling, but before you take the wires off, look at what you've got. IIf the fixture and the wiring in the house is newer, you'll see a white wire wired to a white wire and a black wire (and maybe a blue one) wired to a black wire. You may see the green, or grounding wire, or it may be just tucked away somewhere. If your fixture is not color coded, but your house wiring is, get some masking tape and a sharpie and label which fixture wire was attached to which color wiring in the house. If your neither your fixture nor your house wiring was color coded, then you're dealing with a very simple fixture and the direction of the flow of current is not such a big deal. Simple light fixtures with simple switches in them can be like that. So after everything is labeled, go ahead and disconnect the wires. If you're not replacing the fixture with something newer, make sure you wire-nut the loose wires in the wall and put a nice, solid, blank cover plate over the box in the wall. Ok, now comes the fun part. TO WIRE UP THE FIXTURE: seriously, the easiest way to do it is to go to a local hardware store, old fixture in hand, and ask somebody to show you what to do. Once you've done it once, you'll find out it's SUPER DUPER EASY and you'll be fine. You can pick up really cool fixtures from Habitat for Humanity "ReStores" which sell salvaged building supplies. If you totally disassemble a light fixture, rub it down a little with steel wool, and spray a few coats of rustoleum on it, you can get some pretty jazzy fixtures for very, very little cost. Take lots of pics with your digital camera while reverse engineering to help you in the reassembly state. This can be fun to do! I've converted some ugly old dark metallic and shiny brass finished fixtures to plug-ins - wall sconces make great reading lamps that way. ANd the ReStore has all kinds of funky globes for the light fixtures for just a few bucks each. Have fun! <><><> As always, if you are in doubt about what to do, the best advice anyone should give you is to call a licensed electrician to advise what work is needed.
Before you do any work yourself
on electrical circuits, equipment or appliances,
always use a test meter to ensure the circuit is, in fact, de-energized.
IF YOU ARE NOT ALREADY SURE YOU CAN DO THIS JOB
SAFELY AND COMPETENTLY
REFER THIS WORK TO QUALIFIED PROFESSIONALS.
Does a dishwasher need a dedicated circuit?
Asked by Wiki User
Dishwashers do not have to be on a dedicated circuit, according to NEC codes. Neither do refrigerators. Electric Ranges and OTR Microwave Hoods and Hood Fans do.
First, always ascertain the appliances that will be in the room and regularly used, and calculate their wattage or look it up in the specs found on the appliance or in its manual.
The dishwasher issue is a falsehood espoused by many kitchen designers, home inspectors and electricians who have apparently substituted their own opinions as being code. I just read all of the applicable NEC codes. They are readily available for purchase or for free at your local library. Consulting it yourself is the best bet. It does not specify a dedicated circuit for the dishwasher. It can be on a branch circuit for the kitchen, but if it's sharing the circuit with other appliances, then it must not use more than 50% of a branch circuit's load capacity. So that in effect creates a dedicated circuit requirement IF your circuit is a 15 amp circuit. If it's a 20 amp, you may have capacity room for a small load appliance such as the disposal or refrigerator, depending on load calculations (Volts x Amps = Watts (Load). But if you use a 30 amp or higher circuit capacity, then you can comply with code much easier if other small appliances are on it. NEC 210.23
What might cause low voltage at one outlet on a multioutlet circuit?
Asked by Wiki User
its an overload on the circuit breaker the 3 outlets are on.. many times groups of outlets are on different circuit breakers.. even though they are in the same room... especially if some are on a gfi outlet
Why is light fixture hot?
Asked by Wiki User
When electricity runs through the fillament in a light bulb, the electrons move so fast that they generate heat, which also creates light. Light bulbs actually create more heat than light.
What is 13 amp plug?
Asked by Wiki User
It's the standard Type 'G' 3-pin plug used in the UK for electrical equipment and appliances. It should always contain a cartridge fuse of the right size to match the current or "amperage" drawn by the equipment/appliance it is supplying with power. Standard fuses to fit the plug are available in 13 amp, 5 amp, 3 amp and 1 amp sizes. For more information see the Related Link and the answer to the Related Question shown below.
What is the size of the copper wire for a 100 amp service?
Asked by Wiki User
A #3 copper conductor with an insulation rating of 75 or 90 degrees C is rated at 100 and 105 amps respectively.
