97 replies to this topic

[The Architect]

Since we have a generator thread, why not a transfer switch thread.

I'll start.

What transfer switch should one use on a 6500/7000 watt Generator.

Need to power:

1. Hot water tank
2. Fridge
3. TV
4. three rooms

[PeepSight]

The Architect said:

Since we have a generator thread, why not a transfer switch thread.

I'll start.

What transfer switch should one use on a 6500/7000 watt Generator?

From what I read on the transfer switches (the extra box you hook up next to your original box) it is based upon the amps and circuits that you want to back up which will correlate to the size of the generator you will be using. (30amp / 50amp/ 100 amp boxes)
I see it as you are backing up for basics (heat/hot water /refrigeration / some lights) or comfort (add all lights / washer-dryer / TV-cable-internet) or luxury (add pool / air conditioning / automated ammo loader).
I would like to know what the installed price is for the three levels of panels. :)

[Lemming]

A good thread.  I can live with the maze of extension cords for things like the fridge and all (given how rarely I need them), but my furnace is hard-wired in, so it's that's a trickier situation.  

A furnace only transfer switch is fairly affordable.  http://www.homedepot...gId=10053  OTOH I'm not sure I'd install it myself.  During the recent unpleasantness I opened up electrical box on the side of my furnace, figuring I'd unwire from the house and put a pigtail on "for the duration".  It's a remarkable spaghetti factory in there what with all the connections to the thermostats, circulator and oil pumps, etc.  Hopefully more modern systems are laid out in a more organized fashion then a fist full of wire-nuts.

It looks like a multi-circuit transfer switch, particularly with the electrician's time, may cost you more than the genset.

[The Architect]

I figure all the electrical connections feed back to the panel to power my hot water tank/oil burner pump..

[BLAMMO]

I can't believe we don't have a member who's a licensed electrician, and can answer any and all questions.

[the blur]

forget the TV, since cable/fios is likely down anyway.  also, if you have a natural gas water heater, you have one less worry.   From the type of questions I am hearing, I'd recommend calling in a professional.

[the blur]

The Architect said:

I figure all the electrical connections feed back to the panel to power my hot water tank/oil burner pump..

all the connections lead back to the transformer, which means if you don't do it properly, your powering the neigborhood, and the next neighborhoodn after that.  so you really need a transfer switch to isolate what you need powered.   which can be your entire house, or just a few circuits.

[The Architect]

BLAMMO said:

I can't believe we don't have a member who's a licensed electrician, and can answer any and all questions.

Yea. I might have an idea..
http://www.longislan...315414008.9635/

[willgrah]

I am not an electrician, nor do I play one on TV.  However and maybe someone correct me if wrong is that you are limited to the largest connection on your generator not the total output.  For instance, if you only have a 30 AMP twistlock output (240 Volt) on you generator you are limited to 30 AMPS of power to the switch regardless of the overall output of the genny.  If it is like mine 2 x  20 amp 100 outlets and 1 30 amp, total is 70 amps but no greater than 30 at that one connection.  Past that it is just a matter of lines on the transfer switch assuming is a 30 amp and making sure that you don't exceed that total output with devices.   Regular standby generators do not suffer from this problem because they are hard wired for 100 or 200 amps.  I don't believe you can go much higher than 30 on an extension cord.  The downside to portable generators.   That being said 30 amps will run what you have with no problem, divide your expected wattage using the chart by 120 and that will give you the required amps at one time.    30 amps is 3600 watts.   You should be fine, just a matter of how many places you want to send it at one time.    

[The Architect]

willgrah said:

I am not an electrician, nor do I play one on TV.  However and maybe someone correct me if wrong is that you are limited to the largest connection on your generator not the total output.  For instance, if you only have a 30 AMP twistlock output (240 Volt) on you generator you are limited to 30 AMPS of power to the switch regardless of the overall output of the genny.  If it is like mine 2 x  20 amp 100 outlets and 1 30 amp, total is 70 amps but no greater than 30 at that one connection.  Past that it is just a matter of lines on the transfer switch assuming is a 30 amp and making sure that you don't exceed that total output with devices.   Regular standby generators do not suffer from this problem because they are hard wired for 100 or 200 amps.  I don't believe you can go much higher than 30 on an extension cord.  The downside to portable generators.   That being said 30 amps will run what you have with no problem, divide your expected wattage using the chart by 120 and that will give you the required amps at one time.    30 amps is 3600 watts.   You should be fine, just a matter of how many places you want to send it at one time.    

If this is the case, then purchasing a large generator isn't needed then?

I mean, if you can only use the 30 amp 220V twist lock (and the max watts = 3600 [30 amps]) into the transfer switch buying a 6500/7000 watt generator is an over kill then? Unless you can also use the 110 outlets on the generator to power additional outlets with use of an extension cord..?

[frank57]

Is your hotwater source electric gas or oil , if its electric you will need a very large generator. Most people i know have oil heat and a 60 amp
transfer switch  is large enough  with a 6000 watt generator any  load electric hot water or stove  consumes alot of power< resistive> back feeding your boiler
is dangerous if you do not dissconect the feed from the panel thats why you need a transferswitch :)

[willgrah]

You are correct that you can still use the other outlets at the same time.  For instance I have a Briggs 5600/8500, 70 amps total output but cannot use it unless I hook up 4 110 cords and one 240 cord.  

[The Architect]

frank57 said:

Is your hotwater source electric gas or oil , if its electric you will need a very large generator. Most people i know have oil heat and a 60 amp
transfer switch  is large enough  with a 6000 watt generator any  load electric hot water or stove  consumes alot of power< resistive> back feeding your boiler
is dangerous if you do not dissconect the feed from the panel thats why you need a transferswitch :)

I have an oil burner that produces hot water to the 60 gallon water [storage] tank. The storage tank requires electricity to keep it 'hot'.
So I need to have power to the oil burner pump as well.

[Tonto]

good thread  :)

[frank57]

the reason you need a large enough generator is because motors create a an inrush currnet thats why the lights dim when the boiler starts or the frig
so if your not going to control the situation you could create an undervoltage and damage your boiler pumpfan motor resistive loads like  toaster etc
do not do this but draw alot of power to heat things

[frank57]

you only need to run the boiler the circulator is pumping the water thru the tank to keep the water hot, so that tank should stay hot for a while
even with the boiler off

[The Architect]

frank57 said:

you only need to run the boiler the circulator is pumping the water thru the tank to keep the water hot, so that tank should stay hot for a while
even with the boiler off

Good news.  


Do you know the amount of power needed for the boiler?

[frank57]

Architect   thats a nice system the circulator that pumps water thru the heat exchanger draws very little power but when it runs
it cycles your boiler to heat the stored water that circulator runs off a thermostate on the storage tank, :) my father had the same system i installed
a time clock for him so it would not run in the off hours not the boiler just the circulator so he would not make hot water
in the middle of the nite. i think the oil companys may offer that now

[frank57]

what else do you want to run in the house

[the blur]

you need to run the oil burner head, and the circulator, and all the controls.  There are no guessing games here.  look at the name plate ratings on the boiler, and then the pump, and add them up.   even better, take an amp meter, and get accurate readings on the black wire coming into the boiler.

also, buy the largest generator you can afford, because when your motors start up, they will drag the voltage way down.

I wouldn't go less than 6500 watts.  This way you can run a small A/C unit if you drop all the other loads.   also the amps available are 1/2 if the loads are 230volts.