Does a 3 phase transformer in a building still use electricity if no power is on, inside or outside the bldg?

Question

We just moved out of a 6,000 sqft industrial bldg and still get $65 monthly electric bill for a building that is unoccupied with no inside or outside lights left on. There is a 3 phase voltage transformer (480V-208V/120V) in the building that makes a constant humming noise that makes me think it is using electricity 24/7. Does this account for the rather high electric bill for an empty building? Occasionally real estate people will show the bldg to prospective tentants, so we leave the master power switch on for them to see inside. If the master switch is turned off, would this stop the power usage and end the ridiculous bills? Any suggestions?

Thank you.

Answer 1

Okay - you're either the building owner or the last known tenant.

In the first case, you're liable for the electric charges to the facility, unless you've got it written into a tenant agreement that they're paying ... and you have a tenant. In the second case, the actual building owners have tucked the payment of electric utilities into your rental contract ... and as the last known tenant, you get the bill until you turn the 'title' for the service back over to the owners. (By the way, both of these cases work the same for residential properties!)

The commercial electric rate (in most areas) is comprised of a Service charge, a Demand charge, an Energy charge, and an Energy Cost Adjustment.

SERVICE CHARGE: Customer Charge is a meter usage charge on each metered service. This charge covers the utility's overhead costs associated with meter reading, customer services, billing, service calls, and meter maintenance. The monthly service charge for commercial customers can easily be as high as $100.00

DEMAND CHARGE: The billing demand shall be the customer's greatest (insert ime limit here) demand, in kilowatts, incurred during the month for which the bill is rendered, but no less than (insert percentage here) of the highest billing demand during the preceding 11 months or (insert arbitrary kW value here), whichever is greater.

ENERGY CHARGE: The energy charge is the amount you pay for each kilowatt hour that you use. The rate is broken up into two blocks with the rate per kilowatt hour declining with the higher block of consumption.

ENERGY COST ADJUSTMENT: Prior to each billing month a calculation is made to determine the adjustment amount to be charged for each energy unit consumed during that billing period. Since the utility's electric rate structure includes fuel cost recovery, only a portion of energy costs will be collected through the application of the energy adjustment clause.

As to whether there's something left on in your building drawing power ... lights, maybe, or an alarm system of some sort. The transformer does NOT act as a power draw unless there's something requiring current on the inside (downstream side) of the building. Note that this draw COULD include a small heater for maintaining the transformer oil temperature.

(The humming you hear is the power flow in the 'upstream' or utility side of the transformer. It is primarily caused by relatively high-voltage connections and the predominant 60-Hertz signal, rather than by actual power 'flow' ... also referred to as amperes.)

By getting hit with a $65 bill every month, it sounds to me like you're paying for the privilege of having metered power, and nothing else. Unless you divest yourself of building ownership (by getting a new tenant - or if you've merely been a tenant by transferring ownership back to the actual owners of the property), you'll keep having to pay the bill. Or cut power to the structure completely by telling the utility that it's empty, and then it will be the new tenants' responsibility to go through the hassle of connecting. (Speaking from experience - that's NOT the way to get good tenants quickly! There's just too much space available for them to go elsewhere where they don't have to do all the legwork.)

Answer 2

Yes the building must have 3 phase power for you to use a 3 phase piece of equipment. The reason 3 phase equipment is cheaper than single phase is because the equipment is smaller and requires less internal insulation. A single phase device draws more than 3 times the electrical current of a single phase device for the same amount of work. This means thicker insulation between the windings of the motor. In addition for large applications, single phase motors are not very common so they become "special order" type devices. If your warehouse is of any size at all, it should have 3 phase power available on the power pole. The building for sure has two of the phases already wired to the power panel. It might be time to consider upgrading the electrical to 3 phase.

Answer 3

The answer is yes. Part of the charge may be a "just because you have electrical service" charge

Answer 4

Yes, the transformer uses power unless it is turned off...