Why can't I find a 50A GE circuit breaker with GFCI?

Question

I trying to run a 50A circuit to an outbuilding (sauna) from an existing outbuilding (detached garage). I know there are multiple approaches, but my current plan is to add a 50A GFCI breaker to the garage panel to feed the sauna.

The panel in the garage is a GE TM20DC. I spent an hour looking for a GE 50A, double-pole, GFCI breaker with no luck. HD lists one, but it is out of stock. The best I could come up with was a used one (THQL2150GFT) on Amazon for $200.

I can't understand why this is so hard to find; I would think that there are a million GE panels out there and anyone putting in a hot tub needs one of these breakers. I'm very new to this so maybe I'm missing something obvious. I started looking for a compatible breaker from a different company, but that's not a short putt either.

Any help would be appreciated.

Answer 1

"Online" is a bad way to buy electrical gear. 98% of electrical sales and 99.9% of specialty item sales are to licensed electricians. They shop at electrical supply houses, who are cheaper (big box store being cheapest is a lie; that's only true on a few loss-leader items.) Electrical gear is heavy for its cost, so it's very easy to have orders where shipping > item cost. That's a bad look, so sellers fold the shipping cost into the item price (which bites them when the customer returns the item). All this adds up to: anybody who tries to sell electrical gear mail-order gets nothing but novices for customers, and they are high-support and high-returns. So nobody makes an effort to rep electrical gear online; we see whole product categories with zero mail order sellers.

So your best bet is to grab the old Yellow Pages (of course, they're online now) and look under "Electrical supply houses". Call them and find one that is a GE dealer. They will know how to get it.

I started looking for a compatible breaker from a different company, but that's not a short putt either.

The only line compatible with GE panels is Eaton CL, and they don't make 2-pole GFCI breakers. CL is a specialist line made specifically for competitor panels. The common 1" wide breaker types (HOM, BR, QP and THQL) are not interchangeable with each other and the vast majority of bus stab burn-ups we see are alien breakers.

Answer 2

One way around this could be the use of a 'spa panel'. Use a normal 50A breaker in your detached garage where it's difficult to locate a GFCI breaker. Then use a spa panel right next to the sauna fed from that breaker. This panel will be a disconnect with a 50A or 60A GFCI breaker in it, effectively a special case of a very small subpanel. Unfortunately, because 50A GFCI breakers are not a cheap item, this will not be a much cheaper solution. It will let you use a breaker series that has commonly available GFCIs though, and give you the benefit of having a disconnect adjacent to the sauna, something which might be required based on local code anyway.

Answer 3

240V GFCI is a relatively new thing. 240V GFCI for large circuits is an even newer thing. This commonly comes up with EV charging, and there the solution is to hardwire the EVSE (the "charger") to avoid the GFCI breaker requirement because EVSE includes built-in GFCI.

In your situation, the solution is to not use a GFCI breaker as the feed breaker. Instead, install GFCI breakers for each branch circuit in the sauna panel. A typical setup is that most circuits in that subpanel will be much smaller (15A, 20A, occasionally larger) and therefore GFCI breakers will be much more readily available.

While it is not likely an issue for a typical sauna subpanel, keep in mind that due to the low US GFCI threshold current (6 ma), cumulative leakage current from multiple circuits can trip a large GFCI. That is different from many other places where a whole-house RCD is used with a threshold typically around 30 ma. If you put an entire house on a US 6 ma GFCI it would likely result in too many nuisance trips. 50A subpanel with 3 or 4 circuits would probably be OK - if you could find the 50A GFCI breaker.

A few quick notes that apply to any new outbuilding subpanel:

• Ground rods required (normally 2, if it is a new building and you can put an ufer ground then that's better)
• 4-wire connection - hot/hot/neutral/ground
• Local disconnect required. That can be a separate disconnect (like an air conditioner disconnect) but you can also use a "main breaker" in a subpanel (true main breaker or backfed, locked down, main breaker used as a main breaker).