Iwire.
What I wanted to know is when do have to use a 2-pole breaker or when tie handles are not allowed?
OK I think I can help out.
240.20 Ungrounded Conductors.
(A) Overcurrent Device Required.
A fuse or an overcurrent trip unit of a circuit breaker shall be connected in series with each ungrounded conductor. A combination of a current transformer and overcurrent relay shall be considered equivalent to an overcurrent trip unit.
FPN:For motor circuits, see Parts III, IV, V, and X of Article 430.
(B) Circuit Breaker as Overcurrent Device. Circuit breakers shall open all ungrounded conductors of the circuit unless otherwise permitted in 240.20(B)(1), (B)(2), and (B)(3).
(1) Multiwire Branch Circuit. Except where limited by 210.4(B), individual single-pole circuit breakers, with or without approved handle ties, shall be permitted as the protection for each ungrounded conductor of multiwire branch circuits that serve only single-phase line-to-neutral loads.
(2) Grounded Single-Phase and 3-wire dc Circuits. In grounded systems, individual single-pole circuit breakers with approved handle ties shall be permitted as the protection for each ungrounded conductor for line-to-line connected loads for single-phase circuits or 3-wire, direct-current circuits.
(3) 3-Phase and 2-Phase Systems. For line-to-line loads in 4-wire, 3-phase systems or 5-wire, 2-phase systems having a grounded neutral and no conductor operating at a voltage greater than permitted in 210.6, individual single-pole circuit breakers with approved handle ties shall be permitted as the protection for each ungrounded conductor.
![[Linked Image]](https://www.electrical-contractor.net/forum/iw/HandleTies.JPG)
Examples of circuits in which approved handle ties are permitted according to 240.20(B)(2) or 240.20(B)(3).
It is interesting to note that we can use handle ties on loads such as dryers and ranges.
I think most of us assume a common trip breaker is required.
[This message has been edited by iwire (edited 04-09-2006).]
