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Hi,
General question for CEC.
Example 2/0 al wire for underground residential service.
Should table 53 be used for conductors direct burial. (12-012 (1)),
Or, should the underground configuration in rule 4-004 (1) (d) be used?
(Diagram B4-3)
 

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For underground residential services:

6-300 Installation of underground consumer’s service conductors
(1) Except where a deviation has been allowed in accordance with Rule 2-030, consumer’s service conductors
that are located underground shall be
(a) installed in rigid conduit, or electrical non-metallic tubing permitted only for the underground
portion of the tubing run, and be of a type for use in wet locations in accordance with Rule 4-008(1);
or
(b) a single- or multiple-conductor cable for service entrance use below ground in accordance with
Rule 4-008(1), provided that
(i) the installation is in accordance with Rule 12-012; and
(ii) the cable is without splice or joint except
(A) in metering equipment located on the line side of the service box; or
(B) where a cable transition is made to meet the requirements of Rule 4-006.

So the burial depths must be according to table 53.
 

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Personally I've never seen parallel feeds to a residential service. And as far as I know residential services are always considered continuous. Can you give examples of residential loads that would be considered noncontinuous?

I have never seen a residential load that was considered continuous. Rarely are they on for 3 hours or more everyday
 

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I have never seen a residential load that was considered continuous. Rarely are they on for 3 hours or more everyday
Actually by NEC the water heater is one continuous load but generally speaking the loads in a home are not classified as continuous.
 

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I was definitely wrong about the service being continuous. But I would think that branch circuits are still considered continuous for the most part, unless there is another code I missed. :whistling2:

8-104 Maximum circuit loading (see Appendix B)
(1) The ampere rating of a consumer’s service, feeder, or branch circuit shall be the ampere rating of the
overcurrent device protecting the circuit or the ampacity of the conductors, whichever is less.
(2) The calculated load in a circuit shall not exceed the ampere rating of the circuit.
(3) The calculated load in a consumer’s service, feeder, or branch circuit shall be considered a continuous load
unless it can be shown that in normal operation it will not persist for
(a) a total of more than 1 h in any two-hour period if the load does not exceed 225 A; or
(b) a total of more than 3 h in any six-hour period if the load exceeds 225 A.

So for most residential circuits, like lights, stove, fridge, etc., I think it would be hard to show it won't be on for less than an hour in any given two hour period. Again, unless I've missed another code, and I'm gonna get schooled again.:blink:
 

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Really?

8-304 Maximum number of outlets per circuit (see Appendix I)
(1) There shall be not more than 12 outlets on any 2-wire branch circuit, except as permitted by other Rules
of this Code.
(2) Such outlets shall be considered to be rated at not less than 1 A per outlet, except as permitted by
Subrule (3).

12a is exactly 80% of 15a.
 

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Explain to me how 12 outlets in a residence is continuous. Tell me how a kitchen counter circuit is continuous or the garage outlets or exterior outlets and for that matter an entire lighting cir. There is no way that these circuits are continuous IMO.
 

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Seems like it can be argued both ways. Assumimg a 15a branch circuit would you consider any current draw for an hour in a 2hr peroid to be continuous, or would it have to be maxed out at 12a? If any current draw then things like computers, clock radios, tassimo/ coffee makers on the counters, block heaters(winter), smokes detectors on lighting circuits, and generally anything plugged in with a display on it or drawing current in standby mode.
 

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Seems like it can be argued both ways. Assumimg a 15a branch circuit would you consider any current draw for an hour in a 2hr peroid to be continuous, or would it have to be maxed out at 12a? If any current draw then things like computers, clock radios, tassimo/ coffee makers on the counters, block heaters(winter), smokes detectors on lighting circuits, and generally anything plugged in with a display on it or drawing current in standby mode.
All those things mentioned may be on for 3 hrs or more but the circuit is generally not drawing 12 amps for a 15 amp cir or 16 amps for a 20 amp cir. There is no way I can see a typical residential circuit as continuous...Sorry
 

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Explain to me how 12 outlets in a residence is continuous. Tell me how a kitchen counter circuit is continuous or the garage outlets or exterior outlets and for that matter an entire lighting cir. There is no way that these circuits are continuous IMO.
How can you prove that someone is not going to be running a vacuum for an hour on a circuit with 12 outlets? How can you prove that someone is not going to be running a saw in a garage for an hour at any given time? How can you prove that someone is not going to be running a blender in the kitchen for an hour at any given time? And lights are on for an hour or more very frequently. All of these are really good examples of continuous loads according to the rule I quoted, but that's just me.
 

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All those things mentioned may be on for 3 hrs or more but the circuit is generally not drawing 12 amps for a 15 amp cir or 16 amps for a 20 amp cir. There is no way I can see a typical residential circuit as continuous...Sorry
Maybe I'm missing something with not knowing the NEC. But the Canadian Code doesn't determine a load as being continuous or non-continuous because of the percentage of the circuit load it is. It is time based. We then have a max circuit load for continuous or non-continuous. We can only load a circuit to 80% if it is considered continuous, or 100% if it is considered non-continuous. So for us, saying a circuit is drawing 12 out of 15 amps doesn't determine whether or not it is continuous.
 

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8-200 (3) Notwithstanding Rule 86-302, the total load calculated in accordance with either Subrule (1) or (2) shall not be considered to be a continuous load for application of Rule 8-104.

Also 8-202(2)
We've already caught that for the service conductors, but now we're on to discussing residential branch circuits and whether or not they would be continuous. Any thoughts?
 

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crookcirca80 said:
We've already caught that for the service conductors, but now we're on to discussing residential branch circuits and whether or not they would be continuous. Any thoughts?
(3) The calculated load in a consumer’s service, feeder, or branch circuit shall be considered a continuous load
unless it can be shown that in normal operation it will not persist for
(a) a total of more than 1 h in any two-hour period if the load does not exceed 225 A;

I'm guessing what is normal is going to be very debatable. But I also found this

8-302 Connected loads
(2) A load of a cyclic or intermittent nature shall be classified as continuous unless it meets the requirements of Rule 8-104(3).

So fridge,freezer,ac are all cyclical. Kind of a tough one guys
 
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