Mark, I think you’re forgetting about the all-important blower fan in a gas-fired furnace. That said, the reason the code requires furnaces to be hardwired is to ensure that the blower interlock system can’t be bypassed. An electrical interlock ties a heat recover ventilator to circulation air blower operation of a forced-air furnace system. This ensure that the blower circulates supply and return air within the structure. A plug-in power source leads to the possibility that this interlock could be accidentally defeated, resulting in an overheat within the flame box. -mel
On Aug 31, 2021, at 3:38 AM, Mark Tinka <mark@tinka.africa> wrote:
On 8/31/21 12:26, Forrest Christian (List Account) wrote:
Yes. Or any other furnace where the electricity is only used for circulation of the heat. Gas fired Hot water furnaces would be another example where there is minimal electricity used to run the furnace controls and circulate the hot water.
Gas-fired furnaces or heaters should not have an impact because the only electrical requirement is to fire up the pilot light.
But fully-electric heating has a much higher impact on energy sources (heat pumps being the least).
I believe typical electric central furnaces are anywhere between 10kW - 15kW systems. Would a standard 4kVA - 8kVA generator for average Jane cut it? Not sure.
Then again, I live in a more forgiving climate, so I have a very limited need to understand this better.
But I can understand why the code has not caught up to this yet, and insists on hard-wiring the devices... because the majority of home and buildings will still be using all-electric equipment that require plenty of energy, where things can go wrong if you allow Jane to just run her suicide cord any way she may like. Yes, there may be more folk moving over to other energy sources that eliminate or reduce the need for electricity, but the code has to cater for the wider demographic.
Mark.