The Generator company is installing a temporary feed for a 1200 amp I-line panel so that a ATS that feeds it can be changed out. This is a emergency system at a hospital. The load study done shows a max 630 amp load. The technician says that he can install 2 temporary 400 amp 3 pole I-line breakers and parallel feed this panelboard. I don't understand how this would work. How would the load balance between the 2 temporary breakers when it will be connected to one 800 amp breaker at the temporary generator. Will this work?
Temp 800 amp feeder to I-line panel.
- Thread starter wferg
- Start date
- Status
- Location
- New Jersey
- Occupation
- Journeyman Electrician
Electrically it will work, the load will divide on the two 400 amp CB's but I' thinking that there has to be a violation for paralleling the output of two 400 amp breakers.
electrofelon
Senior Member
- Location
- Cherry Valley NY, Seattle, WA
- Occupation
- Electrician
As long as each conductor set is close to the same length the load should divide close to evenly. I don't really see a problem other than maybe a violation of the parallel conductor rules
- Location
- Illinois
- Occupation
- retired electrician
While it should work just fine, it is not something I would do a panel that feeds loads in a hospital.
This is being done by Gen Tech and they are setting 3 temp ATS's and 1 3000 amp switchboard so that we can upgrade the existing EM equipment. They are charging 1 million to do the temp set up for 40 days.
We are installing 3 new 1.5 MW paralleling generators and a Siemens 6000 amp EM switchboard and refeeding the 6 existing ATS's. I have never seen anyone use 2 paralleling breakers to increase load capacity on a panel. I can't do anything like that on a permanent install. I have been in the trade for 45 years.
electrofelon
Senior Member
- Location
- Cherry Valley NY, Seattle, WA
- Occupation
- Electrician
So for a million they can't rustle up an 800A breaker? There is eBay
How will the parallel 400 amp breakers trip simultaneously should something go “KAPUT!”
are the handles mechanically or electrically tied together?
240.8 Fuses or Circuit Breakers in Parallel. Fuses and circuit
breakers shall be permitted to be connected in parallel where
they are factory assembled in parallel and listed as a unit. Individual
fuses, circuit breakers, or combinations thereof shall not
otherwise be connected in parallel.
are the handles mechanically or electrically tied together?
240.8 Fuses or Circuit Breakers in Parallel. Fuses and circuit
breakers shall be permitted to be connected in parallel where
they are factory assembled in parallel and listed as a unit. Individual
fuses, circuit breakers, or combinations thereof shall not
otherwise be connected in parallel.
electrofelon
Senior Member
- Location
- Cherry Valley NY, Seattle, WA
- Occupation
- Electrician
I thought about that, but im not sure it applies. The 400A breakers arent serving any overcurrent purpose, they are just a means to connect the conductors to the bussing.
maybe you right…
still with the protection curves I could see where a single 400 would trip before the 800 causing cascading problems.
They were discussing this as a option for the 1 1200 amp board. They were laying out cables today. I don't know what the final option is that there going with. I'll see what they do in next couple of days. I have never seen a parallel breaker set up like they were saying was an option. They are good at what they do. They service a lot of the casinos in Vegas. This group working here are out of Phoenix and Vegas.
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hillbilly1
Senior Member
- Location
- North Georgia mountains
- Occupation
- Owner/electrical contractor
They probably will do parallel generators too, so not that unusual. That way they keep the building up while servicing each one.
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