Is a junction box required when connecting distant groups of panels wired in series?

st4rgut

Is it OK to skip the junction box when connecting groups of panels that are wired in series? For example I want to wire three groups of panels in String 1 below. Could I thread the wires through conduit to reach groups of panels on different roof faces and mount the conduit to the railing without a junction box?


I found an example of what I want to do on YouTube   (18:50). The conduit bridges the gap between the two groups of panels, and the conduit is affixed to the railing. I'd like to do this as well, but not sure if it's code compliant.
 

littleharbor2

I see two problems here

1, You have 13 panels in 3 different orientations in string one. You will get the lowest panels current output dictating all panels current down to the same level. Very poor design.

2, String #2 has 10 panels. The voltage output from those 10 panels vs. the voltage from string #1 will be lower. When you combine the two strings the voltage of string 1 will be pulled down toward the lower voltage from string 2.

As to your question, Yes you can skip the combiner box with only two strings due to the fact that you don't need to fuse each string in this case. All you need is a set of parallel connectors to combine the two strings 

st4rgut

Thank you. Actually I am using a solaredge optimizer for each panel so I'm allowed to mix different orientations in the same string.

littleharbor2

That makes a big difference. Details matter when asking questions. So you have a Solar Edge inverter and are grid tied, correct? Does your inverter have multiple MPPT inputs?

A junction box is for combining multiple strings in parallel. Looks like you are just trying to series connect panels in multiple locations with space in between. Extension cables, in conduit where needed should work.

Dave Angelini

You really should ask the building department where you live. This should be inspected if you have Home Insurance.  

Especially if on a roof !

If this caused a fire, the Insurance company could deny the claim.

st4rgut

yes, I am connecting two strings to a Solar Edge inverter that is grid tied. Thank you for the explanations.