What are benefits of a subpanel over pre configured 6 , 8 or 10 circuit Transfer Switch Kits? which one is better for Portable Generator?

Question

I am planning for a Generator based power back up. Need to have the back up to run the sump pump in case the there is a power outage in Spring when the snow melts making water flow in my sump pit and if I dont have power back-up, I might end up in flooded basement. Running sump pump was the original need but when I am investing money into a generator, why not have some more things run on generator so the list grew. Now we are at following wish list if we can run these ( may be not at once) Sump Pump ( Original need) ; Well Pump (I know it is 230 Volts) ; Furnace ( Fuel is natural gas) ; Hot Water tank ( Fuel is natural gas) ; Fridge ; Microwave or stove to cook something ; Internet router ; Septic Tank Pump ; An outlet to charge our phones, laptops etc

When I search the internet, two main results appear- One is interlock at the main panel so that whole house has electricity from the generator and then I can pick and chose what to run and what not and second choice normally is these transfer switch kits as the link below https://www.amazon.ca/Reliance-Controls-6-Circuit-Generator-Generators/dp/B000BQN4T2/ref=cm_cr_arp_d_product_top?ie=UTF8

Then I read through some of the diy.stackexchange, some experienced users have advised against these 6 or 8 or 10 circuit transfer switch kits as evident from the thread below

Adding a manual transfer switch to handle a portable generator for my house

They said that a sub panel will be more appropriate. I want to do a good work even if bit more expensive. Can some of you please advise, what is advantage of sub panel over these transfer switch kits? Here are some pictures of panel

Answer 1

Cost

On cost, those transfer switches typically cost between $350 and $550 depending on number of switches.

A 12-space subpanel is around $40, interlock $30, 2 breakers for the interlock $10 each, plus a breaker in your main panel (normally $10, but ??? with your panel). That gives 8 "spaces" for 8-16 circuits.

So you're talking $100 for a 12-space, or only a little more for a 24- or 30-space subpanel.

For you, a subpanel gives you a future

If I were you, instantly and without hesitation I would choose a 40-space or 42-space main-breaker panel for around $150, plus typically a $60 interlock for a panel of that size. With the generator breaker we are at $220.

Why would I do that? Real easy. That "generator subpanel" can become your new main panel. It has 40 honest spaces (80 circuits under post-CTL rules) so you can easily fit every circuit you have now in your 20-space 40-circuit FPE panel. Once you migrate all your circuits to your "subpanel" at your leisure, you have an electrician move the main service wires to it. And the dangerous FPE panel is out of the picture.

When you finally go to get rid of that FPE panel and presumably hire an electrician, if the electrician finds a "transfer switch" it will add extra time to the job untangling all those wires, and nothing will be reusable. If the electrician finds that 40-space "generator subpanel", it'll be like "Wow, you've already done 2/3 of this job for me, I just need to upgrade this to a main panel and we're done!"

---

---

Could you DIY all that?

Moving the main service wires requires the cooperation of the electric company, so that part will need a permit to be pulled, because the power company will insist on seeing it to turn the power back on.

Honestly, I'd come at it from a slightly different approach. One of the vexations in modern wiring is the totally unfused wire run from the meter to the main panel. NEC 2020 now requires an external "meter-main", which puts the main breaker at the meter, and means that wire is now fused and your "main panel" can be de-energized entirely. So when able, I would have the meter pan changed out to a meter-main. It requires coordination with the power company since they must remove your service drop... but it's a simple project of small scope. Neutrals and grounds need to be separated in the FPE panel, and a ground wire added to the meter to panel feeder (if it's not already in metal conduit).

Once the meter-main is in place, your main feeder wiring is protected by a breaker you can turn off, which makes all of the above a lot easier to DIY.

Answer 2

The big problem with Reliance 6 circuit style beside lack of flexibility is they create a rats nest in the panel.

But your bigger issue is Federal Pacific, see Wikipedia:

After the 1979 sale of Federal Pacific Electric to Reliance Electric, a unit of Exxon Corporation, Reliance reported to the U.S. Consumer Product Safety Commission that the Stab-Lok breakers and panels did not meet the requirements published by Underwriters Laboratories, even though the products bore UL markings. The CPSC performed its own testing and concluded:

Commission testing confirmed that these breakers fail certain UL calibration test requirement...