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 > Has anyone upgraded to a QD 8000 from an LP unit

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Mile High

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Posted: 08/31/17 11:08am Link  |  Quote  |  Print  |  Notify Moderator

CA Traveler wrote:

Lots of misinformation here. Split phase is used to identify 120/240V power. The QD 8000 is not 120/240V but rather 2 120V circuits. This means each hot line will carry 4000/120 = 33A and the neutral will carry the combined current of 66A. You may need to replace the wiring from the gen to the ATS and then to the CB panel. And you will need to upgrade the ATS to one that will handle the increased neutral amps.
There are no ATS upgrades for RVs. They already handle the full common neutral load from the pedestal split phase system, and the generator produces far less than that, even if it is not split phase. RV ATS are standard units designed for a 50A service or 30A service. The size of the generator has no impact on the ATS, or the size of wire to the CB, unless the generator is going to exceed the pedestal service. It doesn't help to unravel misinformation with more misinformation.


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MrWizard

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Posted: 08/31/17 11:45am Link  |  Quote  |  Print  |  Notify Moderator

He has a 50 amp RV, (2)50 breakers and shore cord

He already has a 50 ats and wiring
The 8000 watt generator is still 30% less than the 12000 Watts of the ats and wiring, needed for shore power use

Yes he might need bigger wire between the generator and the ats
Maybe, depending on length, if the existing wire is 6ga, he's legal and good,


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CA Traveler

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Posted: 08/31/17 02:10pm Link  |  Quote  |  Print  |  Notify Moderator

Mike,

Yes correctly rated ATSs are available and as I recall the neutral is rated for 70A. The QD 8000 has a maximum of 66A on the neutral because it is NOT a 120/240V gen. The neutral amps for the 2 hots add for the gen.

Wiz has it right to check the current wiring for length, gauge etc. However it's unlikely that the OPs current gen has adequate wiring for the QD 8000. The larger neutral is needed from the gen to the ATS and then from the ATS to the CB panel. And the OPs hots from the gen to the ATS may also be undersized for the larger gen.


Mile High wrote:

CA Traveler wrote:

Lots of misinformation here. Split phase is used to identify 120/240V power. The QD 8000 is not 120/240V but rather 2 120V circuits. This means each hot line will carry 4000/120 = 33A and the neutral will carry the combined current of 66A. You may need to replace the wiring from the gen to the ATS and then to the CB panel. And you will need to upgrade the ATS to one that will handle the increased neutral amps.
There are no ATS upgrades for RVs. They already handle the full common neutral load from the pedestal split phase system, and the generator produces far less than that, even if it is not split phase. RV ATS are standard units designed for a 50A service or 30A service. The size of the generator has no impact on the ATS, or the size of wire to the CB, unless the generator is going to exceed the pedestal service. It doesn't help to unravel misinformation with more misinformation.



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Mile High

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Posted: 08/31/17 03:17pm Link  |  Quote  |  Print  |  Notify Moderator

CA Traveler wrote:

Mike,

Yes correctly rated ATSs are available and as I recall the neutral is rated for 70A. The QD 8000 has a maximum of 66A on the neutral because it is NOT a 120/240V gen. The neutral amps for the 2 hots add for the gen.

Wiz has it right to check the current wiring for length, gauge etc. However it's unlikely that the OPs current gen has adequate wiring for the QD 8000. The larger neutral is needed from the gen to the ATS and then from the ATS to the CB panel. And the OPs hots from the gen to the ATS may also be undersized for the larger gen.


Mile High wrote:

CA Traveler wrote:

Lots of misinformation here. Split phase is used to identify 120/240V power. The QD 8000 is not 120/240V but rather 2 120V circuits. This means each hot line will carry 4000/120 = 33A and the neutral will carry the combined current of 66A. You may need to replace the wiring from the gen to the ATS and then to the CB panel. And you will need to upgrade the ATS to one that will handle the increased neutral amps.
There are no ATS upgrades for RVs. They already handle the full common neutral load from the pedestal split phase system, and the generator produces far less than that, even if it is not split phase. RV ATS are standard units designed for a 50A service or 30A service. The size of the generator has no impact on the ATS, or the size of wire to the CB, unless the generator is going to exceed the pedestal service. It doesn't help to unravel misinformation with more misinformation.
You aren't understanding -

The 50A ATS are all the same - they are not rated differently even by brand. The same 50A ATS is used for the 4,000 microlight as it is for the 12,000W diesels on an RV.

The wiring to the CB and ATS is sized for the shore line, not the generator. Everything from the shore line to the CB is sized for 50A service on both legs including neutral. The only wiring that will need upgraded is from the generator to the transfer switch to accommodate the higher output from the 8000 genset.

You are making way more out of this than it needs to be.

CA Traveler

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Posted: 08/31/17 03:51pm Link  |  Quote  |  Print  |  Notify Moderator

No Mike you don't understand. Yes the 4000W gen only puts out 33A so the wiring is fine. The QD 8000 on the other hand has 66A on the neutral and a larger neutral wire is needed to the ATS and then on to the CB panel. BOTH of these wires will carry 66A at full gen output. And the ATS gen neutral and relays need to carry 66A. Hence the wiring to the CB and ATS is sized for the larger load which is 66A for the gen neutral.

You might be interested to know that even on my prior rig with a QD 7500 Monaco used a larger neutral from the gen to the CB panel.

And you are making way less of this than it needs to be.

I'm certainly fine if the OP wants to use the current wiring. But he can make an informed choice.

Mile High

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Posted: 08/31/17 05:02pm Link  |  Quote  |  Print  |  Notify Moderator

CA Traveler wrote:

No Mike you don't understand. Yes the 4000W gen only puts out 33A so the wiring is fine. The QD 8000 on the other hand has 66A on the neutral and a larger neutral wire is needed to the ATS and then on to the CB panel. BOTH of these wires will carry 66A at full gen output. And the ATS gen neutral and relays need to carry 66A. Hence the wiring to the CB and ATS is sized for the larger load which is 66A for the gen neutral.

You might be interested to know that even on my prior rig with a QD 7500 Monaco used a larger neutral from the gen to the CB panel.

And you are making way less of this than it needs to be.

I'm certainly fine if the OP wants to use the current wiring. But he can make an informed choice.
You are just plain wrong!

We agree, the wiring from the gen to the ATS needs upsized - but the wire from the ATS to the CB is ALREADY sized for shore line, so it is more than sufficient to carry the 66A, because it is already sized carrying 100A on the neutral!

I'm thinking you may not have worked on the RV side of this, or installed a generator system, but the cable to the CB from the ATS is common for both shore line and generator, so it is already sized for the larger.

* This post was edited 08/31/17 05:10pm by Mile High *

CA Traveler

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Posted: 08/31/17 05:25pm Link  |  Quote  |  Print  |  Notify Moderator

Mike, You've just demonstrated that you don't understand a 120/240V circuit like the 50A RV. That's OK because we all have to learn.

Just so you know both hot's and the neutral are the exact same wire size. The secondary winding on the utility transformer is a single phase center tapped winding and the center tap is the neutral. Due to this type of circuit the center tap or neutral wire carries the difference in amps of the two hots. ie If one hot has 30A and the other 20A then the neutral has 10A. A 120/240V 50A RV circuit neutral does not carry the sum of the two hot lines. Hence none of the 3 wires will carry more than 50A due to the 50A CB on the hot lines.

The QD 8000 has 2 33A 120V circuits and it's common neutral does carry the sum of both of the hot wires. Hence the wiring needs to handle 66A all the way to the CB panel.

* This post was edited 08/31/17 05:32pm by CA Traveler *

Mile High

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Posted: 08/31/17 06:44pm Link  |  Quote  |  Print  |  Notify Moderator

CA Traveler wrote:

Mike, You've just demonstrated that you don't understand a 120/240V circuit like the 50A RV. That's OK because we all have to learn.

Just so you know both hot's and the neutral are the exact same wire size. The secondary winding on the utility transformer is a single phase center tapped winding and the center tap is the neutral. Due to this type of circuit the center tap or neutral wire carries the difference in amps of the two hots. ie If one hot has 30A and the other 20A then the neutral has 10A. A 120/240V 50A RV circuit neutral does not carry the sum of the two hot lines. Hence none of the 3 wires will carry more than 50A due to the 50A CB on the hot lines.

The QD 8000 has 2 33A 120V circuits and it's common neutral does carry the sum of both of the hot wires. Hence the wiring needs to handle 66A all the way to the CB panel.
So you are saying the neutral wire size for an 8000K generator needs to be larger than that for the 50A 240 pedestal shore line to the CB. I think you are totally over thinking this.

Mile High

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Posted: 08/31/17 07:14pm Link  |  Quote  |  Print  |  Notify Moderator

CA Traveler wrote:

Mike, You've just demonstrated that you don't understand a 120/240V circuit like the 50A RV. That's OK because we all have to learn.

Just so you know both hot's and the neutral are the exact same wire size. The secondary winding on the utility transformer is a single phase center tapped winding and the center tap is the neutral. Due to this type of circuit the center tap or neutral wire carries the difference in amps of the two hots. ie If one hot has 30A and the other 20A then the neutral has 10A. A 120/240V 50A RV circuit neutral does not carry the sum of the two hot lines. Hence none of the 3 wires will carry more than 50A due to the 50A CB on the hot lines.

The QD 8000 has 2 33A 120V circuits and it's common neutral does carry the sum of both of the hot wires. Hence the wiring needs to handle 66A all the way to the CB panel.


Here is what is wrong with your theory - My 8,000K gen is mated to a Surge Guard Model 41260 ATS with contactors rated at 50A FLA.

CA Traveler

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Posted: 08/31/17 08:00pm Link  |  Quote  |  Print  |  Notify Moderator

Mike,

It's not theory - it's basic AC Circuits 101. Have you researched this to where you now understand the QD 8000 has a maximum 66A on the neutral and the RV 50A circuit has a maximum of 50A on the neutral?

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