On Monday, Lisa took the new junction box and set out to enlarge the largest of the "knock-out" holes in it from 1 inch to 1 1/4 inches so it would accept the larger conduit that we are installing. Here she holds the junction box with a length of 1 1/4-inch conduit installed and displays the grinding wheel it took to do it.
This grinding wheel was a cylinder when she started working on the junction box. This is what it looked like when she was finished.
At left is the old junction box with the replacement to the right. Originally, the 6-gauge wires from the main circuit box ran through the conduit to this box, where it connected to the lines running to the RV pedestal. 6-gauge wire is heavy; it needs to be to carry the 50A current. The wires only barely fit into the small junction box. The replacement needs to hold not only the 6-gague wire to the RV, but the new 10-gauge wire running through the same conduit from the circuit breaker. From the new box, the 6-gauge wire will once again connect to the RV line, while the 10-gauge line will continue on to the 30A hot water heater circuit. (Both lines are 220V, with two feeds and one return, with a lighter weight ground line, for a total of eight wires.)
The old junction box will not go to waste. Lisa will use it for the point where the new circuit turns upward through a yet-to-be-drilled hole in the bathroom floor and then up to a disconnect box that will feed the hot water heater. (Modern building codes require a cut-off switch be installed within sight of electric hot water heaters for the safety of the people working on them.)
Both junction boxes mount to under-floor beams. Although not technically required, she plans on running flexible conduit for the wire run from the large box to the small one under the house.
Why all of this fuss over a mere quarter-inch of conduit, you may ask? Here's a side-by-side comparison of how much more volume the extra 1/4-inch gets you.
Lisa put the smaller pipe inside the larger one so as to show just how much bigger the larger one is. We ended up needing all of that space, too. Those wires are thick.
Lisa dug out more around the conduit and removed all of the old conduit from under the house as far as the junction box. She then set the new, larger conduit on top of the old and used the old lines as a guide for cutting the EMT and PVC conduit lines to the right lengths.
We discovered when pulling the old electrical lines out that the electrician who wired the RV pedestal had used nothing but black 6-gauge wire for the feeds and returns (putting white tape on the ends of the return wire) and red 10-gauge wire for the ground (putting green tape on the ends). While this was within code, Lisa considered it lackluster, and we went and bought three new lengths of wire: 6-gauge red (second feed; the existing black line is the first feed), 6-gauge white (return) and 10-gauge green (ground).
On Tuesday, Lisa did some more digging (the new conduit goes slightly deeper than the old), cemented the PVC conduit, attached the EMT, and hooked it up to the circuit box. It was time to start pulling wire.
Lisa used the electrician's fish tape to run a length of pilot string through the conduit. Then we used the string (which is more than twice the length of the conduit) to pull the five different wires through the conduit: the four lines for the RV circuit and a combined 10/3 wire carrying three 10-gauge lines and a lighter ground line for the water heater circuit.
Even with the larger conduit and pilot rope, this was a bit of a challenge. Lisa was under the house at one end of the conduit and I was outside either pulling lines up or pushing them down, depending on which seemed easiest for each line.
As darkness fell, we got the last of the wires through the conduit. Nothing is reconnected yet, but Lisa says that this was by far the hardest part of the project. She was completely beat from all that back-and-forth work under the house and took today off.
Tomorrow Lisa plans to reconnect the RV lines (the main line to the RV pedestal has the proper color coded wires) so we can re-energize that circuit. Then she needs to work on running the 10/3 line through the 3/4-inch flexible conduit in preparation for drilling a hole through the bathroom floor and running conduit up from underneath the house. We figure that wire-pulling job should be much easier than what we did yesterday.