Why 20 amp circuits?

[peter d]

If I was wiring a new home, I would wire it to the CEC rules if I could. :thumbsup: All I'd need is 14/2 and 14/3. :happyyes:

 

[mbrooke]

Running an individual 15 amp circuit to every kitchen receptacle - in most instances gives you more total VA ability in that kitchen than splitting them up over the minimum required two 20 amp circuits, and no reason this shouldn't be able to be a design choice, but this is not any new rule by any means either, think it goes back at least 50-60 years if not more.

Well worded- my exact reasoning behind my opinion that 210.11 is written as design rather then rules protecting life and property. Code should always be written regarding what is trying to be accomplished, not on the belief on how it should specifically go about being done.

 

[kwired]

I'm curious behind your reasoning on 3va being overkill. In no way am I saying your wrong, we may disagree in the end, but you probably know something I do not.

well 1500 Sf home = 4500 VA - 37.5 amps @120 volts. That is before adding individual branch circuit loads, the laundry or SABC's. Outside of times where portable heaters might be in use or window AC's, you are seldom going to draw that level of current if ever, and if you do it won't be for very long.

Well worded- my exact reasoning behind my opinion that 210.11 is written as design rather then rules protecting life and property. Code should always be written regarding what is trying to be accomplished, not on the belief on how it should specifically go about being done.

If you want example of NEC being a design manual, all of 210.52 is design instructions. Some of those rules do make some sense from a safety perspective though.

 

[mbrooke]

well 1500 Sf home = 4500 VA - 37.5 amps @120 volts. That is before adding individual branch circuit loads, the laundry or SABC's. Outside of times where portable heaters might be in use or window AC's, you are seldom going to draw that level of current if ever, and if you do it won't be for very long.


I agree, but in cold climates you would be surprised at the number of these:

If you want example of NEC being a design manual, all of 210.52 is design instructions. Some of those rules do make some sense from a safety perspective though.

Its a fine line- receptacles every X feet of wall space is design, but its one of the few times when it actually saves lives by eliminating the temptation of using extension cords.

 

[jim dungar]

Its a fine line- receptacles every X feet of wall space is design, but its one of the few times when it actually saves lives by eliminating the temptation of using extension cords.

Where does it say that the NEC is not to be used for designing safe electrical installations?

Starting in 2014, the language in 90.1(A) says "the Code is not intended as a design specification or an instruction manual for untrained persons.

The NEC is not detailed enough to be a complete set of specifications, especially for untrained persons, but that does not mean it cannot contain any design criteria at all. It is also not to be used as an instruction manual, particularly for untrained persons, but that does not preclude it from providing some installation requirements. For example, 358.24 tells how bends in EMT should be made, but nowhere does it tell specifically what tools to use or how to use them.

 

[mbrooke]

Where does it say that the NEC is not to be used for designing safe electrical installations?

Starting in 2014, the language in 90.1(A) says "the Code is not intended as a design specification or an instruction manual for untrained persons.

The NEC is not detailed enough to be a complete set of specifications, especially for untrained persons, but that does not mean it cannot contain any design criteria at all. It is also not to be used as an instruction manual, particularly for untrained persons, but that does not preclude it from providing some installation requirements. For example, 358.24 tells how bends in EMT should be made, but nowhere does it tell specifically what tools to use or how to use them.

As code is evolving, it is starting to contradict its intentions. In some cases design is inevitable, however every practicable effort should be achieved stating the required goal, not to go about how to do it.

 

[Tony S]

Have they said why it won't work? They are still optional now, correct?


I'm sorry this fraud has taken ground in your country, even though 20 years ago UL and others were poring over BS7671 due to its arc protection capabilities. If can't make stuff like this up.

They’re a recommendation. Where the problem occurs is when an electrician is in court trying to explain why they didn’t follow the recommendation.

As for AFDD’s on a ring circuit. You could have a loose connection anywhere on the ring but the current has an alternative path and so it won’t show as a fault.

 

[kwired]

well 1500 Sf home = 4500 VA - 37.5 amps @120 volts. That is before adding individual branch circuit loads, the laundry or SABC's. Outside of times where portable heaters might be in use or window AC's, you are seldom going to draw that level of current if ever, and if you do it won't be for very long.


I agree, but in cold climates you would be surprised at the number of these:

Its a fine line- receptacles every X feet of wall space is design, but its one of the few times when it actually saves lives by eliminating the temptation of using extension cords.

Cold enough there are plenty of those around here. I hate them. Even the ones that boast they can't start a fire (because exterior surfaces never exceed a certain temperature) still have resulted in melted cord caps/receptacles, or burning a weak splice or device termination. Kitchen appliances, hair dryers, power tools that draw similar amps - don't typically run for long extended periods of time and don't cause such issues nearly as frequently.

They claim to save energy, and users may claim they do as well, but they really become "zone heaters", allowing extra heat in the room they are used in without heating the entire house to a higher level. If you put one in every room and try to maintain same temperature everywhere, it won't cost much different to operate energy wise than a central electric heating system. If it is radiant heater it will feel more comfortable at a lower temperature but that is a benefit of any radiant heater.

 

[mbrooke]

They’re a recommendation. Where the problem occurs is when an electrician is in court trying to explain why they didn’t follow the recommendation.

What if said court was given the evidence they are snake oil?

As for AFDD’s on a ring circuit. You could have a loose connection anywhere on the ring but the current has an alternative path and so it won’t show as a fault.

It won't "show" a fault on a radial either. Thermerater has a fool proof solution, and without nuisance tripping. Why the thermarester isn't an option for your code make me go :blink::huh::blink:

Cold enough there are plenty of those around here. I hate them. Even the ones that boast they can't start a fire (because exterior surfaces never exceed a certain temperature) still have resulted in melted cord caps/receptacles, or burning a weak splice or device termination. Kitchen appliances, hair dryers, power tools that draw similar amps - don't typically run for long extended periods of time and don't cause such issues nearly as frequently.

They claim to save energy, and users may claim they do as well, but they really become "zone heaters", allowing extra heat in the room they are used in without heating the entire house to a higher level. If you put one in every room and try to maintain same temperature everywhere, it won't cost much different to operate energy wise than a central electric heating system. If it is radiant heater it will feel more comfortable at a lower temperature but that is a benefit of any radiant heater.

I agree- its marketing more then anything else. But I will admit on of them is nice, at least in my experience.

 

[kwired]

What if said court was given the evidence they are snake oil?



It won't "show" a fault on a radial either. Thermerater has a fool proof solution, and without nuisance tripping. Why the thermarester isn't an option for your code make me go :blink::huh::blink:

I agree- its marketing more then anything else. But I will admit on of them is nice, at least in my experience.

I'm the kind of guy that will buy the ~$50 not so fancy looking space heater (if I am going to buy one at all) from general hardware section instead of a $400-500 dollar one that looks nice but is nothing but a fancy case with a heater in it. Both will put out 1 watt of heat for every input watt.

 

[mbrooke]

What if said court was given the evidence they are snake oil?



It won't "show" a fault on a radial either. Thermerater has a fool proof solution, and without nuisance tripping. Why the thermarester isn't an option for your code make me go :blink::huh::blink:


I'm the kind of guy that will buy the ~$50 not so fancy looking space heater (if I am going to buy one at all) from general hardware section instead of a $400-500 dollar one that looks nice but is nothing but a fancy case with a heater in it. Both will put out 1 watt of heat for every input watt.

I agree on that as well.

Personally I like the oiled filled radiators, silent and the make the room feel warmer in my experience.

 

[kwired]

I agree on that as well.

Personally I like the oiled filled radiators, silent and the make the room feel warmer in my experience.

Takes same watts to heat same space. Oil filled is just storing heat in the oil and continues to release it after the thermostat has reached setpoint. They do have some radiant heat given off as well - all radiant heaters give a little more comfort that makes the room feel warmer than actual air temp is. Takes longer to heat that oil from a cold start then it takes for non oil filled heater to start warming the room. Watts is watts, difference is mostly management of where the heat goes or how quickly it is transferred.

 

[mbrooke]

Takes same watts to heat same space. Oil filled is just storing heat in the oil and continues to release it after the thermostat has reached setpoint. They do have some radiant heat given off as well - all radiant heaters give a little more comfort that makes the room feel warmer than actual air temp is. Takes longer to heat that oil from a cold start then it takes for non oil filled heater to start warming the room. Watts is watts, difference is mostly management of where the heat goes or how quickly it is transferred.

Yes, yes and yes.

 

[Tony S]

It won't "show" a fault on a radial either. Thermerater has a fool proof solution, and without nuisance tripping. Why the thermarester isn't an option for your code make me go :blink::huh::blink:

Thermarrestor’s were suggested for inclusion in the 18^th but were rejected at the committee stage. I’m not sure why but I’ll have a word with one of the committee members and let you know.

I used something similar in my house 30+ years ago where if the fire extinguisher was removed from its clip it tripped both RCD’s. (Fortunately it was never needed). Our company would sell fire extinguishers to employees for £1, if you had to use it, they replaced it for free.

 

[mbrooke]

Thermarrestor’s were suggested for inclusion in the 18^th but were rejected at the committee stage. I’m not sure why but I’ll have a word with one of the committee members and let you know.

Shows the bias (influence) within the committee. Point of use thermal monitoring does the exact same thing as AFCIs claim to do if not more. Actually arcing is the end stage of joule heating... but none the less one technology is being mandated over the other.

I used something similar in my house 30+ years ago where if the fire extinguisher was removed from its clip it tripped both RCD’s. (Fortunately it was never needed). Our company would sell fire extinguishers to employees for £1, if you had to use it, they replaced it for free.

Well at least said fire extinguishers where full.