Re: Reminder: Never connect a generator to home wiring without transfer switch

[Owen DeLong via NANOG <nanog () nanog org>]

> On Aug 31, 2021, at 03:36 , 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.

Depends… Forced air gas-fired furnaces (as in most central heating systems) also need something to run the 
squirrel-cage blower.

Most gas furnaces that are not forced air these days do require some electricity to run the thermostat, but that’s 
usually generated from the pilot light (very low current 24VAC for the “C” wire).

Don’t get me started on the whole mess that is the C-Wire and the various hacks to accommodate legacy systems that 
don’t have one.

> But fully-electric heating has a much higher impact on energy sources (heat pumps being the least).

Yep.

> 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.

15kW is 1.5kVA in a simple radiant electric heat application. (it’s a simple resistive load with no power factor 
weirdness). Whether you could do this with 4-8kVA depends on what else you’re trying to run.

If you’ve got 3 teenagers all trying to run blow-driers at the same time and you also want to run your electric clothes 
dryer, you’re probably SOL.

If you’re trying to charge a cellphone, a laptop, and run a mostly closed refrigerator/freezer, you’re probably OK.

> Then again, I live in a more forgiving climate, so I have a very limited need to understand this better.

Louisiana actually mostly doesn’t get all that cold. In fact, AC is a more likely issue in Louisiana than heating.
In the winter, Tennessee gets down to ~9.4C on average (49F), which is still well within human tolerance with 
blankets/coats/sleeping bags.
This time of year, it still tends to be fairly warm there, similar to Louisiana (in fact, today’s temperatures in both 
states are nearly identical).

> 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.

There are a multitude of reasons that a suicide cord is a bad idea beyond just the load planning issues and the lack of 
understanding
of load planning by the average consumer. The average consumer probably doesn’t understand that it’s a bad idea to feed 
100A
of current through a “heavy duty” 20A extension cord into a 15A outlet to back-feed 200A panel through a 15A breaker.


Owen