Has anyone used these small residential transfer switches made by APC (Scheider Electric) for standby portable generators? I saw one at a customers home the other day and they seem good. They can load shed if the draw goes over the generators capacity.
The one thing that I didn't like was there was no exterior control of the individual circuits and the overcurrent protection (fuses) are behind the cover, so the average homeowner can't reset/replace when tripped.
Just looking for comments from others who have used the product?
I’ve never actually seen one first hand before, but $513.99 for a 10-circuit panel seems a little steep. I would probably just recommend an interlock kit for $150.00 and put the extra $350.00 into a better generator. I think most customers would prefer to be able to do their own manual load selection and load shedding in an emergency situation rather than having circuits randomly and unexpectedly drop out, but I suppose if they want things to be as hands off as possible then this could be the transfer panel for them.
APC 10-Circuit MSRP
The interlock has the advantage that you are not rewiring branch circuits but load management may be beyond the capability of some homeowners.
The best way is to incorporate this transfer panel and designated emergency circuits into the original design but I doubt many home builders will spend that kind of money on regular houses. It is a nice feature if they do.
This transfer switch has its overload protection (fuses) located behind the front cover. They are not accessible for the owner to replace.
Is this a violation of the code? 240.24?
shortcircuit
It sure sounds like a violation to me. This is what the user manual says in "trouble shooting"
Circuit Fault (no power on a circuit)
Possible Cause: The circuit breaker for this circuit may be tripped, or may have the wrong rating.
Solution: Reset the breaker, or have an electrician upgrade the breaker rating, as required.
Possible Cause: If there is still no power, the fuse may have blown.
Solution: Contact an electrician to replace the fuse.
I suppose they could call this supplemental protection but then it would need coordination with the BCOCD. If they are both the same size it is a race to see who blows.
I’m wondering if maybe the UTS circuit breakers are the automatic resetting type, since they have this text in the Operation, Safety and Warranty PDF. It looks like you have to actually program the circuit Amps to be protected at setup.
Circuit Amp Rating
Warning: This setup option should be configured by a qualified electrician during the initial setup
and installation of the UTS.
Adhere to all national and local electrical codes when setting the Amp ratings for the UTS circuits.
Failure to comply with electrical codes could result in UTS malfunction and damage.
The factory default setting is 15 Amps. The Amps for each circuit on the UTS should
be set to match the Amp rating of the supporting circuit on the building circuit breaker.
According to the manual, the UTS overcurrent protection is Littelfuse KLKR type fuses or equivalent.
I wonder how many homeowners have an insulated fuse puller?
My guess is it will be replaced with an FRN since that is what Home Depot sells.
techie...thats right...there is no circuit breakers with this transfer panel, only individual fuses located behind the removalable front cover...and everything is live with the cover removed. The owner can't shut off a circuit if there was an emergency when on generator supply...or replace a fuse without exposing themselfs to a live condition?
I'll have to look to article 702 to see if this is acceptable?
This Transfer switch has been on the market for a few years and it is listed as a part available from Honda. I can't find another electrician in my area who has used it. Everyone uses the Gen Tran type for portables. First time I've seen one of these APC units... also claims that it is UL 1008 approved?
If this is like all the other small transfer panels, those onboard fuses are bypassed in utility mode and only in the circuit when the switch is in the generator position where the APC’s on board processor and current sensors would likely have control of everything. Likewise when in the generator position the utility side OCP in the normal circuit panel is bypassed, so I don’t think coordination should be an issue. Since you have to set the circuit Amps for each circuit at setup for anything over 15A, I’m guessing the APC’s big brain is monitoring circuit Amps as well as everything else so the only time an internal fuse could probably blow is if the CPU malfunctioned or some other catastrophic event took place in which case simply replacing a fuse would probably be the least of the HO’s problems.
They also mention remote start capability for this unit, but they say the generator must remain plugged in for this function. Would it be a violation to keep a portable backup generator permanently connected with a cord and L14-30 plugs?
APC is a big supplier of Uninterruptable Power Supplies...
So a UPS can also be connected to this transfer switch.
I think the switch is OK...just not sure if some of the design is code compliant. Overcurrent devices for the most part should be readily accessible 240.24
Here is a link to a more informative video on the product...
http://www.hondapowerequipment.com/flash/hp2s/ml.rwp41t91.index.html
I see that for Legally Required Standby Systems, 701.25 Accessibility states that the branch circuit overcurrent devices shall be accessible to authorized persons only, but I don’t see anything at all mentioned in 702 for Optional Standby Systems, which is what a setup like this would normally be. So not sure, but maybe it is up to the manufacturer if they want the HO to be able to access them or not. I may have to flip through the UL white book later on and see if anything pops up.
The loophole in 240.24 is for supplemental protection. I suppose of the APC is monitoring current and holds it below 15 or 20 the fuse should not blow ... or at least that is the design that was presented to U/L.
Greg...the fuses inside the switch aren't supplemental when the unit is operating on generator power...right? So if there is a shortcircuit in a circuit fed by the transfer switch when on standby power, the cartridge fuse inside the unit will blow. Now the owner can't fix that without opening up the unit to replace the fuse. They will need an electrician to do this. Fine with me...I could use the work.
But I thought overcurrent protection should be accessible to the owner to fix/reset safely?
Also the owner can't shut off a circuit if they needed to?
shortcircuit
Well, I haven’t been able to find anything in the UL white book that refers to the overcurrent protection used with these transfer switch type panels and the UL 1008 standard that is mentioned by the manufacturer doesn’t seem to address this either.
Now I’m also wondering how this fancy type of UPS/generator backup transfer panel would handle the bypassing of AFCI and GFCI circuit breaker protection on generator power any different than a regular GenTran or Reliance panel would. This is another reason I generally prefer an interlock kit or dedicated generator backup panel.