Image of a battery bank showing exposed terminals
Does your battery installation comply?
Introduction
The aim of the article is to consider some of the legal requirements and how the regulations have changed or could be applied/interpreted for battery storage systems as used in conjunction with solar PV systems and backup systems.
In this article, a combination of references from different documents are considered. We explore how these regulations could potentially render a large percentage of solar PV installations that contain storage and Backup systems, to be “illegal” or “unsafe”.
Documents considered for this article are indicated below.
- The electrical machinery regulations
- General machinery regulations and
- Installation regulations and
- Wiring Code SANS10142-1
Battery banks.
Batteries store energy that is used on demand (as and when required). The most prominent battery technologies used in SA are lead acid batteries with Li-ion and Flow technologies gaining popularity.
An increasing number of solar installations in grid areas contain batteries or some sort of storage mechanism and a very large percentage of these installations have exposed battery terminals. The general perception is that DC is harmless and exposed terminals on commissioned battery systems are an “acceptable norm”. It is therefore not uncommon to find a Certificate of Compliance being issued in an installation where battery terminals are left exposed.
But what does the wiring code and regulations have to say about exposed terminals? With older versions of some of the standards/regulations, a 50V threshold was provided before insulation became a requirement and for some reason a 48V battery bank is considered to be under 50V. Regulations however do not mention the 50V threshold in updated versions. Despite this threshold, a 48V battery bank can very easily reach 57Volts. During accidental contact, a Direct Current shock can result in injuries that are far more sever than that those caused by Alternating Current.
Regulations
The power supply model as traditionally used by utilities and municipalities, is fairly straight forward. Definitions of point of supply, point of control and point of consumption are clear and very well defined by the installation regulations, wiring code (SANS10142-1) and other regulatory guidelines. With alternative power supplies however, another “point of supply and point of control is created. Although the point of supply and point of control does not directly affect the battery installation ‘per se’ the definitions are mentioned in the regulations and affect the relationship of equipment used in an alternative energy supply in relation to that of the utility; i.e. both are sources that supply power to a point of supply/control.
An electrical installation is defined in the electrical machinery regulations as . . . .
“electrical installation” means any machinery, in or on any premises, used for the transmission of electricity from a point of control to a point of consumption anywhere on the premises, including any article forming part of such an installation irrespective of whether or not it is part of the electrical circuit, . . . .
For this article we only want to look at the definition of “electrical installation” as defined in the electrical installation regulations because the definition of an electrical installation makes reference to the word “machinery”
The scope of the Electrical machinery regulations 2011
“2) These Regulations shall apply to users who generate, transmit or distribute electricity whether overhead or underground to the point of supply”
The regulation further states in Section 6 (1)
An employer or user shall cause enclosed premises housing switch gear and transformers -(g) to be of such construction that persons cannot reach in and touch bare conductors or exposed live parts of the electrical machinery.
and then Section 18(1)
An employer or user shall cause -
(b) all accessible metallic parts of electrical machinery that, though normally not forming part of an electrical circuit, may become live accidentally, to be protected by an insulated covering or to be otherwise enclosed or to be earthed and the resistance of the earth continuity path shall not exceed 0,2 Ohm.
Section 22
The employer or user shall cause bare conductors, other than conductors of a power line which cannot be completely insulated and which is installed on premises, to be so placed as to prevent accidental contact therewith, and warning notices to be prominently displayed at such conductors.
General machinery regulations
3. (1) Every employer or user of machinery shall-
(a) ensure that all machinery used by him, is suitable for the purpose for which it is used, and that it is installed, operated and maintained in such a manner as to prevent the exposure of persons to hazardous or potentially hazardous conditions or circumstances;
(b) in particular cause every exposed and dangerous part of machinery which is within the normal reach of a person to be effectively safeguarded by means of insulation, fencing, screening or guarding, except where an inspector has granted written permission for the omission of such safeguarding;
(2) Where machinery constitutes a danger to persons, the employer or user of machinery concerned shall cause the premises in question to be enclosed, and where such premises are unattended the designated entrances to such premises shall be kept closed and locked.
SANS10142-1
5.1.1 Live parts
It shall not be possible to touch any live part within arm's reach with the
standard test finger (see SANS 60529) Amdt 5
a) during normal operation, or
b) when a cover is removed, unless the cover is removed with the use of
a tool or a key.
Summary
Based on regulations and wiring code all exposed parts are supposed to be insulated regardless of the system voltage and regardless of whether it is AC or DC.
Who we are and what we do.
We do inspections that provide a neutral view on installations, needless to say, we visit a fair number of PV installations. Inspections are based on a checklist we have created that looks at PV installations from a SANS and IEC standards point of view. The checklist is available free of charge. No, we are not A.I.A’s and do not work for the Dept of Labour. We do not do installations and hence the purpose of the inspection is not to try and convince the end-user to rather use us, or anybody else for that matter. The inspection is to test compliance, identify any obvious issues and then make recommendations through a ‘neutral’ report that is issued post the inspection. Three types of inspections are available which could either be a visual, compliance or performance inspection. Visual inspections are performed without testing equipment. Compliance and performance inspections are conducted with Metrel testing equipment which includes a IV curve tester and irradiation tester which was provided by Justin Clarkson from African Instruments. The aim of the report issued subsequent to the inspection is to guide the installer with regards to changes which could be made in order to reduce risk and potentially satisfy any questions the end user may have had regarding the installation.
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