NEC vs. manufacturers installation requirements and guidelines.
NEC vs. manufacturers installation requirements and guidelines.
Are tandem breakers ok to install in new panels. I only need to install one tandem. I can't find anything in the NEC prohibiting their use in new boxes nor in the local electrical code. I try to use tandems in existing boxes only. I'm assuming the AHJ cannot red flag me on this. Thanks
NEC vs. manufacturers installation requirements and guidelines.
An excellent (and often asked) question!
The easiest way to answer this is, the NEC is not the only source for installation details. As a matter of fact, the NEC has very few installation details to begin with. To sum it up the NEC makes a very simple reference... "As per manufacturers installation guidelines". The is a mouthful!!! By making this 5 word statement the NEC pushes the responsibility of installation detail onto the manufacturer.
As far as answering your question, you have to look at the small panel detail graphic (usually on the inside of the panel). This and the wording on the label will explain what type of breakers can be installed in the panel, if tandems are allowed and if so where they would be positioned in the panel.
CTL vs. NON-CTL (Ant discussion about tandems has to touch on this)
I can type all day to explain the difference in tandem circuit breakers but I have a lot to do today so here's a Wiki link...
http://en.wikipedia.org/wiki/Circuit_Total_Limitation
This will help eliminate the old wives tale of "If it fits in the panel, it's code compliant".
Surprisingly (sadly) many inspectors don't know too much about this.
Just my 2-cents (0.00012 cents after adjusting for inflation)
Cheers,
Ken C.