Mr. Merman,
I have kindly responded to your posts and in context to the conversation. A cordial dialog is welcome; however, name calling and personal attacks are not acceptable here.
The general focus of my responses to you have been regarding your continued insistence that a GFCI circuit breaker can be substituted where an AFCI circuit breaker is required by code, something that is simply not the case (in context to code OR function). If you can cite a code section that disputes this fact and supports your claim, then please post it.
I have stated (in response to your remarks) that where an AFCI is required by code and one wishes to forego its use, or substitute a GFCI, then either a locally adopted code or the AHJ would have to bless such a scenario. This is a simple fact of following the law.
If we ignore the code requirement and legal component and speak purely on the merits of the devices, then replacing an AFCI breaker with a GFCI breaker is certainly a safer option than replacing the AFCI breaker with a simple circuit breaker. Nobody here as argued any differently and that simple fact is what has helped bolster the movement whereby many jurisdictions are allowing AFCI waivers in certain conditions where the AFCI can be shown to be a nuisance.
In fact, there is a similar movement to ease (by local code or waiver) some of the GFCI requirements as well. Here is a recent example from Virginia:
http://www.nema.org/Technical/Code-Alerts/Pages/21-November-Virginia.aspx The argument is simple, currently GFCIs are required in garage spaces, regardless of what they power. The housing board sees an issue where many homeowners have refrigeration units in their garages that are exposed to nuisance trips, as well as garage door openers that should be excluded.
You indicated that GFCIs have overcurrent and short circuit protection. I clarified your statement (it was ambiguous, even in context) by pointing out that GFCI circuit breakers have overcurrent/short protection but GFCI receptacles DO NOT. This fact was presented for the clarity of those who may still be following along.
RE: Your views on AFCI, the origin of their mandate, political and financial contexts, etc. I think if you go back and read my remarks (and those of others) in this thread and similar threads, you will find that most of us are not proponents of broad scope of the current code mandate. As to the question of their ability to detect an arc, they do work, albeit so well that they are a nuisance in many environments.
Regarding the "advice" in this thread:
We are dealing with a very simple situation, a renter that needs to power an aquarium. His options are to ask the landlord to extend or install a branch circuit, something that would almost surely trigger an AFCI requirement. He may wish to do this, but the outcome is fairly predictable and not favorable. His other option is to extend the circuit to his aquarium stand using some type of extension cord. The safest way for him to do this is to buy or build a cord with GFCI protection. In that context, multiple GFCIs will be safer for his aquarium inhabitants than a single GFCI (be it at either end of the cord). The advice in this thread (from almost all of the posters) has evolved to reach this same logical conclusion.