Don’t let your “Shark-Bites” come back to bite you!

There has been some discussion about whether push-to-connect type plumbing fittings (Shark-Bites are a common brand name) maintain electrical continuity when using them on metal piping.

As near as I can tell, the unsatisfactory answer is that they are not tested or listed for continuity through them. One thing is certain, any bonding achieved through the connectors is purely “coincidental” as there is certainly no “positive” connection between the brass fitting and the metal pipe.

Coincidental contact between the fitting and the pipe happens when the pipe makes accidental contact with the fitting (intentional contact for this purpose was not designed into the fitting). Whether the pipe is inserted all the way or not, there may be no continuity through the fitting—functional or otherwise.


So what is the definition of electrical continuity–or better yet “functional continuity?” By lining up 3 pennies in a row touching each other, you will have continuity across the pennies, but how would that continuity function under a live load? Would it create an effective ground fault path to trip a breaker if necessary?

Not likely, and likely a bonding jumper would be necessary around such plumbing fittings.

In fact there is actual documentation from the manufacturer of Shark-Bite, push-to-connect fittings that recommends jumping around the fittings when used with metal piping.

I set up a little experiment with an assembly of 4 push-to-connect fittings to see how much voltage drop there would be. The voltage drop of the circuit through the soldered pipe assembly on the left (without any push-in-connectors) was 4.6%.


The voltage drop through the push-in-connector assembly without any load was up-and-down but generally around 25%. By merely wiggling the assembly a bit the voltage drop varied up and down. Under the load of a 1500 watt space heater, the fluctuation varied widely from 45% to 75%.

It was interesting to note that when I initially started the test, the assembly was plugged into an AFCI protected circuit. As soon as I turned on the 1500 watt space heater, the AFCI breaker tripped. I could actually hear the arcing at the connections. Seems like the AFCI functioned as intended.

The experiment and test results pictured above were completed on a circuit that was not AFCI protected.  I found the results to be pretty dramatic.

This is a side view of the assembly, painted black for thermal uniformity.


Here is the thermal image of the assembly prior to turning on the heater.


Here is an image of the temperature within the assembly after 60 seconds.


Here is the temperatures within the assembly after 2 minutes: >356 degrees F.  My decision that it probably was not a good idea to continue the experiment game next, as it appeared I now had two heaters in the room instead of one.

So while this little experiment may lack in some controls that would be present if the same testing was done in a professional laboratory, or by Myth Busters, it is likely good enough to conclude that push-in-connectors cannot be relied upon as a ground fault path and could even be a fire hazard if the piping they were in were to become energized.

The bottom line is that proper bonding is necessary around push-in-connectors installed in metal piping systems—or better yet, perhaps other types of fittings should be used.


By Charles Buell, Real Estate Inspections in Seattle

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Why is the bedroom cold with the heat cranked up?

Cold bedrooms can really put a damper on things–in fact having heat in bedrooms is one of the code requirements to make the room habitable space.

It is actually not that common to find bedrooms with no heat supplied to them. If they do not have heat it is usually because it is new construction and somebody “forgot” that room, or in older homes with crawl spaces the ductwork sometimes becomes disconnected.

Most people won’t put up with not having any heat in bedrooms, so the issue usually gets resolved pretty quickly.

I had a very interesting situation at a recent inspection. There was hot air, in the 90’s, at all registers in the home except for one in one of the bedrooms, and that register measured in the upper 60’s.

Cool air at heat register

Cool air at heat register

As soon as I walked into this bedroom the room was noticeably cooler than in all other parts of the home.

It turned out that, very near the furnace plenum, where the heat duct for that room left the furnace there was a fresh air intake into the ductwork from outdoors just below it. In the picture one can see the overlaid blue arrow that is the air intake duct.

Air intake in conflict with heating and cooling

Air intake in conflict with heating and cooling

All the time the furnace was running this cold air coming in from outside was diluting the heated air being delivered to the room (as indicated by the red arrow). This air intake damper (indicated by the blue line) was designed to be operated manually and should be closed in the winter. It was designed to be opened in the summer so that fresh air could be distributed throughout the home with the furnace in “fan” mode.

As you can see in the following picture the air is moving into the air intake enough to pull tissue paper up against it.

Air intake at the outside of the home

Air intake at the outside of the home

We would not use this type of system today. Similar systems today work with electronic dampers that would automatically stay closed in “heating/cooling” mode and automatically open in “fan” mode.

While this room would never have been as cold as outdoors, I have to wonder how long it has been unsatisfactory like this. Did the owners wonder why it was cooler and just put up with it? In summer in cooling mode this room would likely not have been as cool as other rooms as the hot outdoor air would be mixing with the cooler conditioned air.

As soon as the damper was closed, the room immediately warmed up just like the other rooms in the home.

Some of this work just isn’t rocket science.


By Charles Buell, Real Estate Inspections in Seattle

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Limp as a Geoduck at low tide–it can be exhausting work at times fighting the tides!!

I have posted many times about bathroom exhaust vents improperly terminating in attics.

When we first started installing mechanical ventilation in bathrooms, the requirements for where they terminated, merely stated that they needed to be ducted to the “exterior.” All around the country installers have assumed that the attic was “outdoors,” in terms of a place to terminate these vents.

We have learned over time that the attic is not only NOT outdoors, but that the attic can be a very bad place to vent a lot of warm moist air. This became even truer as we stopped “heating” our attics (because there was little to no insulation).

Here we can see a couple of bathroom vent ducts lying on an Attic floor like a couple of relaxed Geoducks at low tide.


Can you see where moisture has been staining the plywood at the ends of the ducts?

The roof sheathing can get very cold and moisture can and will condense on these cold surfaces. It will also contribute to ice-damming in areas prone to that problem.

It is not uncommon to see staining of the wood and even mold or mold-like fungal growth present in the area where the vents terminate, as can be seen at this vent terminating near bird-blocking.


Can you see where moisture has been staining the roof sheathing?

Inspectors will point out vent ducting that is aimed at gable vents, roof vents, and soffit bird-blocking.


The vents actually may work for a while, but these vents have their own job to do and should not be compromised by stuffing vent pipes in them. The screens at these vents will become clogged with lint rendering them less than fully functional for either their own job or the job of the exhaust fan vents.


Can you see the staining around the nail points from excessive moisture in the attic?

Sometimes there is no duct at all and sometimes the duct runs out through the soffits.


Venting out through soffits is not a good idea as the moist air can just find its way back into the attic if there are any other soffit vents or bird blocking nearby.


This is a new installation and already there is some staining of the wood above the vent.

If you look back at the second picture, where the vent terminates in the attic at the bird-blocking, and then look at the following picture, you can see the kind of staining and mold or mold-like fungal growth that is common in the overhangs of homes that have vents terminating at the bird-blocking.


In time the screens will plug up and more of the moisture will then stay in the attic.  Sometimes this staining tells me the vents terminate at the soffits even before I actually see it in the attic.

Generally speaking it is best to run the vents through the roof or through a side wall to a proper cap with a back-draft damper (as is required in most areas that are complying with Energy Codes).

Now wasn’t that exhausting?


By Charles Buell, Real Estate Inspections in Seattle

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