Powerboost 7.2kW Powering House - Which transfer switch works best?

[capkmo]

Thank you so much for this information. I had my electrician scheduled to install the interlock next week, I would’ve been quite disappointed!

@Hullguy hopefully you can provide more guidance. I have my electrician coming out October 1st. I sent him the information you shared here and his response was “No matter what, you cannot separate the ground and neutral in your panel. Unless you have a main breaker ahead of it, which you don’t have”
Could my panel be different or should I press for the manual transfer switch vs interlock?
I searched and could not find another thread answering this. Thank you in advance

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[Gros Ventre]

@Hullguy hopefully you can provide more guidance. I have my electrician coming out October 1st. I sent him the information you shared here and his response was “No matter what, you cannot separate the ground and neutral in your panel. Unless you have a main breaker ahead of it, which you don’t have”
Could my panel be different or should I press for the manual transfer switch vs interlock?
I searched and could not find another thread answering this. Thank you in advance

Your electrician is not quite correct. It depends on the local electrical codes. In my neck of the woods the requirement is for the bonding to be done out at the meter base. I was specifically instructed to remove the "green screw" in the breaker panel where the bonding normally occurs in many codes. His words may be correct for your local codes, but not necessarily correct for other codes. What is most important is that there only be a single bonding point. Can the bonding inside the truck suffice? Well electrically yes, however your local codes may specify yes or no. So check your codes.

 

[capkmo]

Your electrician is not quite correct. It depends on the local electrical codes. In my neck of the woods the requirement is for the bonding to be done out at the meter base. I was specifically instructed to remove the "green screw" in the breaker panel where the bonding normally occurs in many codes. His words may be correct for your local codes, but not necessarily correct for other codes. What is most important is that there only be a single bonding point. Can the bonding inside the truck suffice? Well electrically yes, however your local codes may specify yes or no. So check your codes.

Thank you! This is extremely helpful. I’ll pass the information along to him and hopefully I’ll have this thing setup right before winter. Thank you all again

 

[Hullguy]

@Hullguy hopefully you can provide more guidance. I have my electrician coming out October 1st. I sent him the information you shared here and his response was “No matter what, you cannot separate the ground and neutral in your panel. Unless you have a main breaker ahead of it, which you don’t have”
Could my panel be different or should I press for the manual transfer switch vs interlock?
I searched and could not find another thread answering this. Thank you in advance

Sometimes your main breaker and the Ground/Neutral connection is in the meter socket on the outside of the house.
If this is so, it should have no bearing on installing a neutral switching transfer switch. These instructions are for a Generac neutral switching transfer switch. Forward them to your electrician.
https://www.generac.com/globalasset...al/homelink-transfer-switch-owners-manual.pdf

 

[BobbyG]

I'm looking to purchase a transfer switch and can't decide which to buy. The
Generac
Upgradeable Manual Transfer Switch Kit for 8 Circuits
or the
Reliance Controls
10-Circuit 30 Amp Manual Transfer Switch Kit

Do you know if the 50AMP 10 circuit Generac will work with the Powerboost? Thinking future generator upgrade.

 

[BobbyG]

I'm looking to purchase a transfer switch and can't decide which to buy. The
Generac
Upgradeable Manual Transfer Switch Kit for 8 Circuits
or the
Reliance Controls
10-Circuit 30 Amp Manual Transfer Switch Kit

Finished my Generac 6854 install this week. I installed and wired the transfer switch and 30 amp inlet receptacle and paid an electrician to wire it back to my breaker box. I thought I was stuck with the 8 or 10 circuits but using mini tandem breakers he got me up to (12) 120 volt circuits plus (2) 240 volt circuits to run my 2.5 ton AC. Had already installed a Micro-Air Soft Start, knocking the in-rush down from over 50 amps to 12-17 amps. Put all circuits in service and made sure the AC was running and only used half of my truck's capacity.

One observation about the Generac box. There are 12 neutral landing post with screws. We used all 12 and needed one more for the AC circuit 10 gauge wire and were able to land at #13 at the bottom of the neutral buss by taking an unused screw from the buss on the breaker box.

 

[hpwjr]

I am installing the Reliance Controls manual transfer switch. What ground and neutral problems will I encounter that would cause a fault at the truck?

 

[HammaMan]

I am installing the Reliance Controls manual transfer switch. What ground and neutral problems will I encounter that would cause a fault at the truck?

If it's a 2 pole you'll need a dog bone, if it's a 3 pole, none

 

[Hullguy]

I am installing the Reliance Controls manual transfer switch. What ground and neutral problems will I encounter that would cause a fault at the truck?

An X series Reliance transfer switch would work flawlessly with the PB without the dangerous, unsafe, and against National Electrical Code. If your electrician is any good he would strongly recommend against the dog bone method. Ask your local wire inspector!

 

[hpwjr]

I don’t have the X series. Mine is a 31410C manual transfer switch. What can I do to prevent both the Powerboost fault and sending voltage back up the meter box? I thought the switches on the Reliance box insured you cannot send power back to the incoming house wiring.

 

[hpwjr]

HammaMan says I need a 3pole. Are you talking about the switches on the Reliance. If so, they are all three position switches: house, off, generator. The ground and neutral wires don’t seem to be switched at all; just the hot leads to and from the breakers.

 

[HammaMan]

HammaMan says I need a 3pole. Are you talking about the switches on the Reliance. If so, they are all three position switches: house, off, generator. The ground and neutral wires don’t seem to be switched at all; just the hot leads to and from the breakers.

The PB is a GFI source of power and that cannot be changed unless you build a 'dogbone' to float the ground wire for the specific interconnection means. The dogbone is simply a 1-2' long "extension" to float the ground between the truck and the structure. It's about $34 to build and is used because it's unwise to cut a perfectly healthy gen extension cord to turn into something that could be misused down the line. Granted with most portable gens being bonded, there's no reason to earth it. Electricity derived from a generator is trying to get back to it, not the earth.

This is both safe and not to code.

 

[Hullguy]

The PB is a GFI source of power and that cannot be changed unless you build a 'dogbone' to float the ground wire for the specific interconnection means. The dogbone is simply a 1-2' long "extension" to float the ground between the truck and the structure. It's about $34 to build and is used because it's unwise to cut a perfectly healthy gen extension cord to turn into something that could be misused down the line. Granted with most portable gens being bonded, there's no reason to earth it. Electricity derived from a generator is trying to get back to it, not the earth.

This is both safe and not to code.

How can the dogbone be both safe and not to NEC Code?

 

[Hullguy]

I don’t have the X series. Mine is a 31410C manual transfer switch. What can I do to prevent both the Powerboost fault and sending voltage back up the meter box? I thought the switches on the Reliance box insured you cannot send power back to the incoming house wiring.

Your transfer switch will not work with the Powerboost when wired correctly to National Electrical Code, which was written to protect Life and property.
your transfer switch has double pole switching allowing you to switch each circuit from normal power to backup power. Your normal power service has a neutral/ground bond. The Powerboost also has a neutral/ground bond. The NEC only allows 1 neutral/ground bond. When the truck ”sees” 2 neutral/ground bonds it will shut off under ground fault.
So, to use the Powerboost properly you would need a neutral switching transfer switch, a 3 pole transfer switch. Your transfer switch only switches the 2 hot wires. The three pole transfer switch switches the 2 hots and the neutral from normal utility power to the Powerboost s 2 hots and neutral.
Some say there is a work around, but this work around eliminates your ground wire, which is used to trip your breakers when a short circuit occurs. As a Licensed, Master Electrician with close to 40 years experienc, I do not recommend the dog bone work around.

 

[HammaMan]

Your transfer switch will not work with the Powerboost when wired correctly to National Electrical Code, which was written to protect Life and property.

NEC uses a catch-all approach. Over 30k house fires a year occur with NEC compliance. Given the number of house fires that are NEC compliant, it's easy to mix cause and effect. It's a great set of base rules, but it's not a magic safety as has been drilled into you.

your transfer switch has double pole switching allowing you to switch each circuit from normal power to backup power. Your normal power service has a neutral/ground bond. The Powerboost also has a neutral/ground bond. The NEC only allows 1 neutral/ground bond. When the truck ”sees” 2 neutral/ground bonds it will shut off under ground fault.

Every transformer bonds N/G. GFI can't see a double bond, only when current flows and it sees a delta between what's leaving/returning on the sum of L1, L2, and neutral will it trip. The PB won't trip on a 2 pole switch if all the energy leaving it is feeding 240v circuits. A trip will only occur when 120v is used and redundant N/G return paths return energy on both conductors due to 'missing' current on the neutral as a result of parallel return paths, and only when the ground is allowed to return > 5ma of current. If 2 120v devices of equal current are connected to separate legs, even that isn't enough to trip the GFI with dual bonding. That's nearly impossible to achieve, but still won't trip it if the 2 loads are completely identical.

Some say there is a work around, but this work around eliminates your ground wire, which is used to trip your breakers when a short circuit occurs. As a Licensed, Master Electrician with close to 40 years experienc, I do not recommend the dog bone work around.

There is a clear way to avoid tripping the GFI. It doesn't eliminate the ground wire, it creates 2 separate grounding planes. A short between any 2 hots or the neutral will result in an instant trip for the PB's breaker as it's far more sensitive than any panel circuit breaker tripping at 32 amps with no delay. The PB's breaker will trip before a 20 amp and 15 amp panel breakers will. All GFI and AFI breakers in the structure continue to function as they should. I think you should spend time going deep into grounding / earthing and how/why they came about. It'd provide you with significantly deeper insight into what's going on here. Utility derived hot phases are trying to return to earth due to ubiquitous neutral earth bonding throughout the system. The PB's L1 and L2 are trying to return to it, not the earth. Failing to acknowledge this doesn't make it any less true.

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