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Joined: Feb 2011
Posts: 56
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pooL8 Offline OP
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I want to install 1 - 2000W and 2 - 1500w heaters on one circuit, with one t-stat.
Is there something specific in the cec that says I can't run a 10/2 to the t-stat, from there a 10/2 to 2000W heater and then downsize to 12/2 for the next, and again to 14/2 for the last one?


Joined: Jan 2005
Posts: 5,316
Cat Servant
Member
Pool, your question suggests you need to learn the trade.

We're not plumbers. We don't downsize our wire after each load because the rest of the circuit won't "need" all that electricity.

Instead, we -usually- size the wire according to the size of the breaker (or fuse) we have protecting the circuit. A 20-amp breaker needs a circuit with '20 amp' wire for the ENTIRE circuit.

This is one of the basic principles of electric work. The code won't directly spell it out - but the code will tell you how to size your wire.

Joined: Mar 2004
Posts: 947
T
twh Offline
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Originally Posted by renosteinke
Pool, your question suggests you need to learn the trade.
Nice!

62-108(1)(b) and 62-114(4). To summarize, The ampacity of the wire must be greater than the load and at least 1/3 the rating of the overcurrent device; and, the smaller wire must not be more than 7.5 meters long. Or, it must have an ampacity not less than the load and at least 80% of the overcurrent device; in which case the length isn't limited.

The code specifically allows it.

Joined: Jun 2006
Posts: 613
M
Member
Reno see twh response but I will add another limiter. Bond wire size. This reduction works from a 20 amp breaker because the bonding wire is #14 if loomex is in use. You cannot put larger than a 25 amp breaker or the bond wire is too small for a 30 amp breaker.
You can start out in #12 and at 240 volts use #14 for up to 3600 watts or 15 X 240 volts. (Not 12 X 240) the 20 amp breaker may only supply 16 amps so the #12 may only have 1 amp more on a 20 amp breaker or the full 20 amps on the #12 with a 25 amp breaker for a total load of 4800 watts.
Those 2 rules in section 62 create inspection chaos.

Joined: Mar 2004
Posts: 947
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twh Offline
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The size of the bond conductor didn't hit my radar but now that I look at it, I'm going to challenge your rejection of my work based on ground conductor size.

Maybe #14 loomex was a bad example because 10-814(1) says the bond doesn't need to be larger than the largest ungrounded conductor. (That actually makes sense)

Appendix B 10-814(1) says "In any case, the bonding conductor incorporated into a cable assembly is deemed to be of adequate size for the purposes of this rule." So, I'm not changing out my 12 loomex, either.

In the American version of the CEC (2012) #14, 90C is good for 25 amps, so it can be tied onto a 70 amp circuit subject to the distance limitation.

Are you using Table 16? According to that table, a 14 bond is too small for 14 loomex at 25 amps.

I don't see how this can create inspection chaos. Just pretend there are no rules and you'll be pretty close.

Joined: Jan 2005
Posts: 5,316
Cat Servant
Member
Thanks, guys ,for the corrections. I had failed to note the OP was from Canada, where men are men, and money has a pretty scent laugh

US practice would not allow such downsizing between loads.

I can't say I've ever heard of an "American" version of the Canadian Code. Though I will admit you guys speak a dialect that's a lot closer to what you hear in Minnesota - than what you hear in Yorkshire!

Last edited by renosteinke; 05/28/13 09:18 PM.
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Personally, I like our (USA) way! 14= 15 amps, 12=20 amps, etc.



John
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twh Offline
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Originally Posted by HotLine1
Personally, I like our (USA) way! 14= 15 amps, 12=20 amps, etc.
That was our way before 2012. Now we size our breaker like that but derate from the higher ampacity. I thought I read that was to make our rules consistent with yours. Maybe I'm wrong.

I was wrong once. I said I was wrong and everyone said I was right. I was wrong because I was right.

Joined: Aug 2002
Posts: 402
J
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Depends where you live on your interpretation of CEC

CEC = Canadian Electrical Code
CEC = California Electrical Code.

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twh Offline
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Originally Posted by jdevlin
Depends where you live on your interpretation of CEC

CEC = Canadian Electrical Code
CEC = California Electrical Code.


CEC, eh because it's the CEC eh forum.

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