Combiner

Merry Christmas

rattus

Senior Member
How many of you have heard of a combiner? Just saw a video of some DIY guy making one, and he didn't seem to reallize that he had to have a split phase service to make it work. If you are going to go to this much trouble, why not just install a 240V breaker and outlet?
 

hbiss

EC, Westchester, New York NEC: 2014
Location
Hawthorne, New York NEC: 2014
Occupation
EC
You mean like a "Y" cord that plugs into two 120V receptacles, each on different phases, with a 240 cord cap on the other end? Whatever floats your boat I guess.

-Hal
 

GoldDigger

Moderator
Staff member
Location
Placerville, CA, USA
Occupation
Retired PV System Designer
You mean like a "Y" cord that plugs into two 120V receptacles, each on different phases, with a 240 cord cap on the other end? Whatever floats your boat I guess.

-Hal
More like "Whatever sinks your boat"?
Any regulatory issues aside, if you connect a 240 volt load to such a combiner and unplug one of the two male connectors the exposed prongs will have 120V between hot and neutral, coming from the other receptacle.
Not all that different from hooking up a generator with a suicide cord,,,,

I believe some of the commercial units for that (not listed ?) use two relays in the junction box to prevent that exposure. Neither side is connected to the load unless both sides are energized.
 

jaggedben

Senior Member
Location
Northern California
Occupation
Solar and Energy Storage Installer
Combiner to me means where I bring together multiple solar sources, usually DC but could be used for AC as well.

I have no idea what you are talking about. :p
 

SceneryDriver

Senior Member
Location
NJ
Occupation
Electrical and Automation Designer
More like "Whatever sinks your boat"?
Any regulatory issues aside, if you connect a 240 volt load to such a combiner and unplug one of the two male connectors the exposed prongs will have 120V between hot and neutral, coming from the other receptacle.
Not all that different from hooking up a generator with a suicide cord,,,,

I believe some of the commercial units for that (not listed ?) use two relays in the junction box to prevent that exposure. Neither side is connected to the load unless both sides are energized.
I had to build one of these things years ago to power a piece of 208V single phase equipment for a trade show booth. The venue would supply as many 120V circuit as you wanted, but if you requested a 208V receptacle of any type, they had to "bring in their electrician" to hook up power, which meant plugging into the spider box already present with a twist lock cable. The venue wanted something like $5k to do this.

I built the box in my hotel room, out of parts we bought at a local supply house and we hid it under a table in the trade show booth so the venue goons wouldn't see it. It had a pair of relays that prevented the male connectors from being energized if only one side was plugged in. It worked a treat, and I think I still have it somewhere in my garage.


SceneryDriver
 

Jraef

Moderator
Staff member
Location
San Francisco Bay Area, CA, USA
Occupation
Electrical Engineer
Combiner to me means where I bring together multiple solar sources, usually DC but could be used for AC as well.

I have no idea what you are talking about. :p
I agree, I’ve only heard that term used in the solar industry to refer to the box where all of the panels are connected together. You need to define what you are referring to better.
 

ggunn

PE (Electrical), NABCEP certified
Location
Austin, TX, USA
Occupation
Electrical Engineer - Photovoltaic Systems
Combiner to me means where I bring together multiple solar sources, usually DC but could be used for AC as well.

I have no idea what you are talking about. :p
My take on it is that he wants to make a single 240V connection from two 120V outlets on different legs.
I agree, I’ve only heard that term used in the solar industry to refer to the box where all of the panels are connected together. You need to define what you are referring to better.
Small point - in solar there are DC and AC combiners. DC combiners connect the outputs of module strings in parallel and AC combiners connect the outputs of inverters (or sometimes groups of inverters) in parallel.
 
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