** **

**Original Version**

Rule 20.5-D

**20.5-D.
****Supply Circuits** mean those
circuits which are used for transmitting a supply of electrical energy.

**1)
****Class H Circuits** include the
following:

Constant potential alternating current circuits of 5000 volts or more between any two conductors

Constant potential alternating current circuits of 2900 volts or more between any conductor and ground

Constant potential direct current circuits exceeding 750 volts between any conductor and ground

Constant current circuits of 7.5 amperes or less supplied from transformers or devices having a normal full-load output voltage of 5000 volts or more

Constant current circuits of more than 7.5 amperes supplied from transformers or devices having an open-circuit voltage of 2900 volts or more.

**2)
****Class L Circuits** include the
following:

Constant potential alternating or direct current supply circuits of lower voltage than Class H

Constant current circuits of 7.5 amperes or less supplied from transformers or devices having a normal full-load output voltage less than 5000 volts

Constant current circuits of more than 7.5 amperes supplied from transformers or devices having an open-circuit output voltage less than 2900.

**Strikeout and Underline Version**

Rule 20.5-D

**20.5-D.
****Supply Circuits** mean those
circuits which are used for transmitting a supply of electrical energy.

**1)
****Class E circuits** include constant
potential alternating or direct current circuits of 300,000 volts or more
between any two conductors.

**1****2)****
Class H** Circuits include the
following:

Constant potential alternating current circuits of
5000 volts or more between any two conductors

Constant potential alternating current circuits of
2900 volts or more between any conductor and ground

Constant potential direct current
circuits exceeding 750 volts between any conductor and ground

Constant current circuits of 7.5
amperes or less supplied from transformers or devices having a normal full-load
output voltage of 5000 volts or more

Constant current circuits of more
than 7.5 amperes supplied from transformers or devices having an open-circuit
voltage of 2900 volts or more.

**2****3)****
Class L Circuits** include the
following:

Constant potential alternating or direct current supply circuits of lower voltage than Class H

Constant current circuits of 7.5
amperes or less supplied from transformers or devices having a normal full-load
output voltage less than 5000 volts

Constant current circuits
of more than 7.5 amperes supplied from transformers or devices having an
open-circuit output voltage less than 2900.

**Final Version**

Rule 20.5-D

**20.5-D.
****Supply Circuits** mean those
circuits which are used for transmitting a supply of electrical energy.

**1)
Class E circuits** include constant
potential alternating or direct current circuits of 300,000 volts or more
between any two conductors.

**2)
Class H Circuits** include the
following:

Constant potential alternating current circuits of
5000 volts or more between any two conductors

Constant potential alternating current circuits of
2900 volts or more between any conductor and ground

Constant potential direct current
circuits exceeding 750 volts between any conductor and ground

Constant current circuits of 7.5
amperes or less supplied from transformers or devices having a normal full-load
output voltage of 5000 volts or more

Constant current circuits of more
than 7.5 amperes supplied from transformers or devices having an open-circuit
voltage of 2900 volts or more.

**3)
Class L Circuits** include the
following:

Constant potential alternating or direct current supply circuits of lower voltage than Class H

Constant current circuits of 7.5
amperes or less supplied from transformers or devices having a normal full-load
output voltage less than 5000 volts

Constant current circuits
of more than 7.5 amperes supplied from transformers or devices having an
open-circuit output voltage less than 2900.