What is the difference between 208 volts and 240 volts?

Answer 1

240 volts is a typical single phase voltage (one phase wire and one neutral wire, possibly a ground wire as well) while 208 is a three phase voltage (you will have three phase wires, plus possibly a neutral wire)

208v in a grounded system is actually 120 volts referenced to ground. That is, there are three 120 volt voltages referenced to ground 120 degrees apart.

A typical house will have 120 and 240 volts. These are both single phase, but the utilitiy company's transformer providing this power has a center tap - so three wires from it, one at 0 volts (the neutral or return - usually the center), one at 120 volts, and one at -120 volts referenced to ground.

Answer 2

One way would be to use a voltmeter to measure the voltage between each phase and neutral. <><><>

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.

Answer 3

208V is typically found in three-phase systems, mostly found in commercial settings. 220V (actually 240) is a single phase system typically found in most homes. 208 is the net voltage developed between any pair of the three legs of a 120V three phase distribution. The individual legs are 120V to neutral and 120 degrees out of phase with each other. The 208V is in essence a single phase voltage when used as such. 220/240 is the distribution in a residence where its split single phase - 110/120 between either hot leg and neutral, and 220/240 across the two hot legs which are 180 degrees out of phase. Using equipment rated for 208 with 220/240 service or vice versa is generally not a good idea. Some equipment may be made with an acceptable input range encompassing both but equipment with motors will have trouble getting full performance out of that large a range, heaters sized for the higher end will not work to but about 75% of capacity when run on too low a range (or have a short life when sized for lower volts but used at higher) and incandescant bulbs will burn out quickly or provide vastly decreased light when run on the wrong range. Strictly speaking without some form of regulation or conversion, the input range is too wide for motors, heaters and lights to work comfortably. Electronic equipment with switching regulators are now common that will handle this range, though. However, most electronics are generally run on 110/120 in the US since they don't require high power.

Answer 4

In a three-phase system, the three phases are displaced from each other by 120 electrical degrees, whereas in a two-phase system, the two phases are displaced form each other by 90 electrical degrees.

Three-phase systems may be three-wire or four-wire systems. Two-phase systems may also be three-of four-wire systems. However, a two-phase three-wire system is the equivalent of a three-phase, four-wire, system.

For a three-phase, four-wire, system, the line voltage is 1.732 times the phase voltage.

For a two-phase, three-wire, system, the line voltage is 1.414 times the phase voltage.

Two-phase systems are extremely rare, so the point of your question is unclear.

A two-phase system is not the same as the system (240/120 V) used in North America to supply residential premises, although it is occasionally but incorrectly referred to as such

Answer 5

You will need a piece of equipment that can read voltage. A multimeter with a voltage scale of 300 volts will do. The safest way for you to do this without opening up your house panel is to (in a new house) go to your kitchen counter plugs. Put one lead of your meter into the top right hand slot in the plug. Put the other test lead into the bottom right hand slot of the plug. If the receptacle is a split receptacle you should read the voltage across the two circuits. The reading on the meter will either read 208 or 240 or nothing. If it reads nothing then the receptacle is not split and you should get some one qualified to help you out.

Answer 6

480v 3phase is dangerous than 120v 3phase.