8 AWG for 50 amps?

[LTLFTcomposite]

Since this topic has wandered far OT can I take the opportunity to as if this were your house would you go to the trouble to change that 3 wire dryer connection to four wire? It isn't a terribly long run, 25' of wire should do it, accessible from the attic.

 

[QueenBee]

Since this topic has wandered far OT can I take the opportunity to as if this were your house would you go to the trouble to change that 3 wire dryer connection to four wire? It isn't a terribly long run, 25' of wire should do it, accessible from the attic.

It'll be interesting to hear how Wayne responds. I think if it were my house I would not replace it but would ensure that the chassis is bonded to the nuetral. Then if one wanted to make things even safer installing a 240 volt GFCI breaker for this circuit would probably result in a safer dryer than one with an EGC and nuetral. That would be really simple and are generally under $100 these days.

 

[Valdemar]

One problem with GFCIs is they sometimes stop working, I had to replace several GFCI outlets over the years, so they have to be tested regularly. Replacing a failed breaker is not difficult but if it requires a call to an electrician it is an additional expense.

But thanks for the idea, I should probably install a GFCI breaker on my oven circuit until It's rewired.

 

[LTLFTcomposite]

In my situation the panel is fully populated and the dryer is already on a tandem breaker (with the AC as I recall) so no room to expand with gfci.

Part of the rationalization in running the 10/3+G for the dryer is I could repurpose the 10/3 w/o G for a hardwired evse, but considering the house only has 100A service along with the panel congestion that might not be too practical (I figured I might be able to find a 50-30 tandem breaker and put the evse on with the range, I think that's the only expansion option remaining)

 

[wwhitney]

So would I replace a 3-wire dryer feed in my house with a new 4-wire dryer feed? Yes, mainly because of my perfectionist tendencies.

Do I recommend that others do so? I'm not sure it is worth it, as long as the dryer on the 3-wire feed has the chassis properly bonded to the neutral. I.e. I bet there are other improvements that could be found that would provide more safety bang for the buck.

Would a GFCI for a 3-wire dryer or oven feed improve safety? Sure. I'm curious as to whether there would be an issue with nuisance trips. If the chassis of the dryer or oven, which is bonded to the neutral, gets electrically connected to something bonded to the EGC, then that neutral/EGC connection could well trip the GFCI. I don't think a person would provide a low enough resistance connection for that to happen. But, for example, if your refrigerator and your 3-wire fed oven are both in contact with a metal backsplash, it could happen.

Part of the rationalization in running the 10/3+G for the dryer is I could repurpose the 10/3 w/o G for a hardwired evse, but considering the house only has 100A service along with the panel congestion that might not be too practical (I figured I might be able to find a 50-30 tandem breaker and put the evse on with the range, I think that's the only expansion option remaining)

Sound like a fine plan. You will be committing a small violation by reidentifying the neutral in the 10/3 w/o ground as an EGC (that is only allowed "Where the conditions of maintenance and supervision ensure that only qualified persons service the installation" [250.119(B)], which generally means industrial installations.) I would check the NEC load calculation for the 100 amp panel, but that is quite conservative. If the current load calculation is under 100 amps, the actual current on the service conductors is very likely under 75 amps at all times. In which case, even if the extra 30 amp EVSE pushes the load calculation over 100 amps, it wouldn't push the actual current on the service conductors over 100 amps.

As far as your panel being full, you could add a subpanel by moving a couple circuits over to the subpanel. That would free up space in the main panel for a breaker for a feeder to the subpanel.

Cheers, Wayne

 

[LTLFTcomposite]

Thanks for the reply. Coincidentally your response is just like my electrician friend with a similar perspective of sweating details. The house has had that 3 wire dryer connection for 30 years, as has probably every other house in the neighborhood apparently without incident, so it sounds like there is no urgency. If and when the time comes an evse is needed at the house running a new line for the dryer makes sense (all of this is in the garage).

As for the load panel calculation I should work through that before adding anything else. House has a 2 1/2 ton AC that runs plenty in the central FL heat, but other than that the range and dryer are the only other significant draws. Heat and water heater are gas. There is gas available at both the dryer and the range but they are both currently electric. I'm guessing ranges are one of those oddities in the calculation, sure you could have a turkey in the oven and all four burners on high but seriously when does that happen in today's lifestyles.