Md. Code Regs. 20.50.07.02 - Voltage Limits

A. Secondary Voltages. The voltage at the utility's service terminals, as installed for each customer, shall be maintained within the Limits specified in the table below. If a utility adopts any standard voltage not included in the table, it shall advise the Commission in order that the Commission may establish appropriate voltage limits. When 3-phase service is provided, the utility shall exercise reasonable care to assure that the phase voltages are balanced.

Standard	Minimum	Maximum
120	114	126
120/208	114/197	126/219
120/240	114/228	126/252
208	197	219
240	216	252
240/416	228/395	252/437
240/480	228/456	252/504
265/460	238/414	278/483
277/480	249/432	291/504
440	396	462
460	414	483
480	432	504
600	540	630

B. Primary Voltages. The following limits shall apply where the utility supplies service at primary voltage:

(1) Industrial Customers. For service rendered principally for industrial or power purposes, the voltage may not exceed 7-1/2 percent above or 7-1/2 percent below the standard nominal voltages as filed in the utility's rules.

(2) Sales For Resale. For service rendered to public utilities and others for resale, the nominal voltage shall be as mutually agreed upon by the parties concerned. The allowable voltage may not exceed 7-1/2 percent above or 7-1/2 percent below the agreed upon nominal voltage without the express approval of the Commission.

(3) Special Contract Exceptions. The limitations in §§B(1) and B(2), of this regulation, do not apply to special contracts in which the customer specifically agrees to accept service with unregulated voltage.

C. Exceptions to Voltage Requirements. It will not be considered a violation when voltages outside of the prescribed limits are caused by any of the following:

(1) Action of the elements;

(2) Service interruptions;

(3) Temporary separation of parts of the system from the main system;

(4) Infrequent fluctuations not exceeding 5 minutes' duration; or

(5) Other causes beyond the control of the utility.

Notes

Md. Code Regs. 20.50.07.02