Let’s face it, the electrical section of a home inspection report can sound like another language. In fact, we even get many calls from electricians with questions about what we’ve written up. The number one electrical question we get is “What is an MWBC?” which we tackled in another blog. The second question we answer the most is, “wasn’t this up to code when the home was built?” This is particularly true when we “write up” double lugged neutrals. Home inspectors aren’t code inspectors, but I can guarantee that double lugged neutrals have never been “up to code”
So what is a double lugged neutral?
It’s simple. This is when two grounded conductors, also called neutrals, or the white wire, are under one screw/terminal. This is a defect because the terminal is only listed for one grounded conductor. One problem, which you can see on the right is that the connections can become loose, which can cause arcing. Another problem is that loosening the grounded conductor of an MWBC in the panel can be a safety hazard if its under load because the current will flow to, and possibly over load one of the circuits in the MWBC.
Well was it code when the home was built? Nope. The NEC (National Electrical Code) made it clear in 2002 that this was prohibited. Section 408.41 states “Each grounded (neutral) conductor within the panelboard must terminate in an individual terminal.” The Virginia Residential Code, which is based from the NEC reflects this in E3706.4 which states “Each grounded conductor shall terminate within the panelboard on an individual terminal that is not also used for another conductor”
So what about homes before that? That is where the disagreement lies. It’s simple though. The NEC states in 110.3 “Equipment must be installed and used in accordance with any instructions included in the listing or labeling requirements” which is reflected in Virginia Residential Code E3403.3 as “Electrical materials, components, devices, fixtures and equipment shall be listed for the application, shall bear the label of an approved agency and shall be installed, and used, or both in accordance with the manufacturer’s installation requirements.
We have been checking these labels for years and so far 100% have stated that neutral terminals are only listed for one conductor. I don’t expect that percentage to change anytime soon. And there you have it. Double lugged neutrals are a defect, were never up to code, and should be corrected. The good news is that it should take an electrician about 1 minute to fix it!