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Sizing Circuit Protection and Conductors Part 1
2013-02-13 20:00:00| Electrical Construction & Maintenance
By Mark Lamendola, Electrical Consultant Understanding which NEC ampacity table to use when sizing circuit protection, and how to determine the minimum ampacity of your conductors read more
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Sizing Feeders, Part 2
2013-02-11 19:51:00| Electrical Construction & Maintenance
One reason Annex D3(a) has a more complicated example of feeder sizing is the circuit is being divided up into different runs with different temperature requirements. But another reason is the neutral calculations are complicated by the fact that the load isn't calculated on the basis of VA per square meter or square foot. Thus, 210.11(B) does not apply and we cannot assume the load is evenly distributed. Before we look at the implications of this, let's see how dividing up the circuit affects the feeder sizing for the ungrounded conductors. read more
Sizing Feeders, Part 2
2013-02-11 19:51:00| Electrical Construction & Maintenance
One reason Annex D3(a) has a more complicated example of feeder sizing is the circuit is being divided up into different runs with different temperature requirements. But another reason is the neutral calculations are complicated by the fact that the load isn't calculated on the basis of VA per square meter or square foot. Thus, 210.11(B) does not apply and we cannot assume the load is evenly distributed. Before we look at the implications of this, let's see how dividing up the circuit affects the feeder sizing for the ungrounded conductors. read more
Sizing Feeders, Part 2
2013-01-22 21:17:00| Electrical Construction & Maintenance
We can see that Annex D and Annex D3(a) of the 2011 provide very different views of feeder sizing. Why is the Annex D3(a) example so much more detailed and complex? For one thing, in Annex D3(a), you size two different types of feeder: ungrounded and grounded. That is, the current-carrying ones and the neutral. read more
Sizing Feeders, Part 2
2013-01-22 21:17:00| Electrical Construction & Maintenance
We can see that Annex D and Annex D3(a) of the 2011 provide very different views of feeder sizing. Why is the Annex D3(a) example so much more detailed and complex? For one thing, in Annex D3(a), you size two different types of feeder: ungrounded and grounded. That is, the current-carrying ones and the neutral. read more
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